FAA FACILITIES

Improved Condition 

Assessment Methods 

Could Better Inform 

Maintenance 

Decisions and CapitalPlanning Efforts

Report to Congressional Committees

September 2013

GAO-13-757

United States Government Accountability Office
United States Government Accountability Office

Highlights of GAO-13-757, a report to 

Congressional Committees

September 2013

FAA FACILITIES

Improved Condition Assessment Methods Could 

Better Inform Maintenance Decisions and Capital- Planning Efforts

Why GAO Did This Study

Of the approximately 1,230 facilities 

that FAA staff occupy, FAA is 

responsible for maintaining over 40 

percent of them—spending over $1 

billion since 2008; most of the 

remaining facilities are leased and 

maintained by the lessors. Yet, 

according to FAA officials, air traffic 

control facilities—the bulk of FAAmaintained facilities—have a current 

maintenance backlog of about $259

million. Deferring maintenance on 

facilities could compromise safe 

airspace operations. 

The FAA Modernization and Reform 

Act of 2012 mandated that GAO study

the condition of FAA-staffed facilities. 

This report addresses, among other 

things, (1) the condition of FAA-staffed 

facilities and the reliability of 

assessment methods; (2) the extent to 

which FAA has responded to identified 

safety deficiencies; and (3) the extent

to which FAA’s actions to ensure that 

its facilities are in good condition follow

leading practices. GAO analyzed data 

and documents from FAA, the 

Department of Labor, and GSA, and

interviewed agency officials and

others, including union representatives. 

What GAO Recommends

To ensure more accurate and reliable 

data to help decision making on its 

facilities’ conditions, GAO is 

recommending that FAA (1) improve 

the precision of the methods used to 

estimate the conditions of uninspected 

terminal facilities and (2) implement a 

plan to improve REMS, consistent with 

sound data collection practices. DOT 

provided technical comments, which 

we incorporated as appropriate.

What GAO Found

According to data provided by FAA and the General Services Administration

(GSA), federally maintained facilities FAA occupies are generally in fair to good 

condition. FAA assesses the condition of staffed facilities in several ways, 

including direct inspections. However, the condition of approximately 75 percent 

of Air Traffic Organization’s (ATO) terminal facilities is based on estimates 

derived from the approximately 25 percent of facilities that have been inspected

over the last 6 years. Our analysis of FAA’s statistical model for estimating the 

condition of uninspected terminal facilities found it to be imprecise; it uses one 

variable—age of the facility—to estimate the facility’s condition. Adding other 

variables that are correlated with condition, such as facility replacement value 

and use, could potentially improve the estimate’s accuracy. In addition, facility 

condition data in FAA’s Real Estate Management System (REMS)—FAA’s 

database for tracking its inventory of real property assets, including the size, 

replacement value, and condition of each asset—are not derived from sound 

data collection practices and did not match facility condition data from ATO or 

other FAA organizational components responsible for maintaining these facilities. 

Inaccuracies in REMS data undermine its usefulness as a management tool. 

Entities Responsible for Maintaining FAA’s Staffed Facilities, 2013

Facility description FAA GSA

Other (incl. 

non-federal Total

Operations (terminal & en-route facilities) 425 -- 137 562

Administrative, technical, training 80 8 583 671

Total 505 8 720 1233

Source: GAO analysis of FAA and GSA data.

FAA has mechanisms to identify and mitigate safety deficiencies at FAA facilities. 

For example, FAA annually conducts a safety and health inspection, as required 

by regulation, at each of its staffed facilities under its Environmental and

Occupational Safety and Health program. Identified deficiencies are tracked to 

ensure they are mitigated. FAA also established safety committees to maintain 

an open channel of communication between employees and managers 

concerning safety matters in the workplace. FAA employees may also report any 

hazards they identify to FAA managers at their facility or, as applicable, to their 

union representative or the Occupational Safety and Health Administration. 

FAA has taken actions to strengthen its capital planning process to help ensure 

its facilities are in good condition. In 2012, FAA created a Facilities Group 

Manager position within ATO to coordinate management of all its operations 

facilities, both staffed and unstaffed. ATO’s Facilities Group Manager is taking 

steps to develop a standard prioritization process focusing on safety, mission 

critical needs, and environmental requirements to modernize and sustain existing 

equipment, facilities, and services; this approach is to be used to develop FAA’s 

future budget requests. FAA is developing a 10-year “Get Well” plan that, among 

other things, is to establish an approach to reduce the maintenance backlog for 

existing facilities. This plan, along with a facilities consolidation report the agency 

is developing in response to the FAA Modernization and Reform Act of 2012, 

should help provide justification and cost projections for maintaining facilities in 

good condition.

View GAO-13-757. For more information, 

contact Gerald Dillingham, 202-512-2834, 

dillinghamg@gao.gov
Page i GAO-13-757 Facilities Condition

Letter 1

Background 4

FAA-Staffed Facilities Are Generally in “Good” to “Fair” Condition, 

but Opportunities Exist to Improve Assessment Methods and 

Condition Information 8

While the Number of Injuries and Illnesses Resulting in FAA’s 

Workers’ Compensation Claims Has Steadily Decreased from 

2007 Through 2011, FAA Has Not Always Met Its Goals for 

Processing Claims 20

FAA Has Taken Steps to Identify and Abate Workplace Hazards 24

FAA Has Taken Steps to Strengthen Its Capital-Planning Process 

and Investment-Decision Practices That Are Generally 

Consistent with Leading Practices 27

Conclusions 34

Recommendations 35

Agency Comments 35

Appendix I Objectives, Scope, and Methodology 37

Appendix II Assessment of FAA’s Statistical Model to Estimate the Condition 

of Terminal Facilities 41

Appendix III GAO Contact and Staff Acknowledgments 52

Tables

Table 1: Maintenance Responsibilities for FAA’s Staffed Facilities, 

2013 5

Table 2: Aggregate FCI and Deferred Maintenance Values for Enroute Air Traffic Control Centers and Inspected Terminal 

Facilities, 2010 through 2012 (Dollars in Millions) 11

Table 3: Comparison of Results from FAA and GAO Models for 

Estimating Deferred Maintenance at Selected Terminal 

Facilities (Dollars in Thousands) 18

Table 4: Top Five Types of Injuries or Illnesses Claims Filed by 

FAA Employees and Accepted by OWCP, 2007 to 2012 21

Contents
Page ii GAO-13-757 Facilities Condition

Table 5: Ratio of FAA Employees to Number of Claims Filed by 

FAA Employees and Accepted by OWCP, 2007 through 

2011 22

Table 6: FAA’s Total Annual Workers’ Compensation Claims 

Payments, 2007 through 2012 23

Table 7: FAA CA-1 and CA-2 Filing Timeliness: Percentage within 

14 Days, Fiscal Year 2007 through 2012 23

Table 8: Leading Capital-Planning Practices for Using Information 

to Make Capital-Investment Decisions 28

Table 9: FAA’s Actual and Projected Capital Improvement Budget 

Line Items, Fiscal Years 2008 through 2017 (Dollars in 

Millions) 34

Table 10: FAA Facilities GAO Contacted 39

Table 11: Results of Replication and Predictive Validation of FAA 

Model 45

Table 12: Results of Replication and Predictive Validation of FAA 

Model 50

Figures

Figure 1: Eight FAA Air Traffic Control Towers Reported to Have 

the Same FCI and Deferred Maintenance Amount 16

Figure 2: Number of Workers’ Compensation Claims of FAA 

Employees Accepted by OWCP, 2007 to 2012 22

Figure 3: Estimated versus Actual Deferred Maintenance in 2010 46
Page iii GAO-13-757 Facilities Condition

Abbreviations:

AIRTRAF Airport Traffic Control Tower Monitoring 

Inspection Program 

ALO Aviation Logistics Organization 

ATO Air Traffic Organization 

BLI budget line item 

CIP Capital Investment Plan 

CMO Certificate Management Office 

EOSH Environmental and Occupational Safety and Health 

FAA Federal Aviation Administration 

FCI Facility Condition Index 

FRPP Federal Real Property Profile 

FSDO Flight Standards District Office 

GSA General Services Administration 

MIDO Manufacturing Inspection District Office

NAS National Airspace System 

NextGen Next Generation Air Transportation System

OMB Office of Management and Budget

OSHECCOM Occupational Safety, Health, and Environmental 

Compliance Committee

OSHA Occupational Safety and Health Administration 

OWCP Office of Workers’ Compensation Programs 

PASS Professional Aviation Safety Specialists 

REMS Real Estate Management System

RMSE root mean squared error 

TRACON Terminal Radar Approach Control 

T-SAP Technical Operations Safety Action Program

WIT Workplace Inspection Tool 

This is a work of the U.S. government and is not subject to copyright protection in the 

United States. The published product may be reproduced and distributed in its entirety 

without further permission from GAO. However, because this work may contain 

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Page 1 GAO-13-757 Facilities Condition

441 G St. N.W.

Washington, DC 20548

September 10, 2013

The Honorable John D. Rockefeller IV

Chairman

The Honorable John Thune

Ranking Member

Committee on Commerce, Science, and Transportation

United States Senate

The Honorable Bill Shuster

Chairman

The Honorable Nick J. Rahall, II

Ranking Member

Committee on Transportation and Infrastructure

House of Representatives

For the Federal Aviation Administration (FAA) to safely operate the most 

complex airspace system in the world, its employees and systems need 

to be housed in facilities that are in good and safe condition. FAA staff 

occupy approximately 1,230 facilities that serve administrative and 

operational functions. FAA is responsible for maintaining almost half of 

these facilities—primarily those used for air traffic control operations. The 

General Services Administration (GSA) maintains the federally owned 

facilities that FAA occupies for administrative purposes. As for the 

remaining facilities, FAA occupies them under leases or other 

agreements whereby the owner provides facility maintenance.

Since 2008, FAA has spent over $1 billion for repairs and improvements 

to the facilities it maintains. While some of the facilities that FAA 

maintains will become excess as a result of planned consolidation, most 

will likely remain in service to support FAA’s mission. To sustain these 

facilities, FAA officials require accurate information about facility condition 

to plan and prioritize maintenance and repairs so that operational needs 

can be met in a safe working environment. FAA’s efforts to address the 

needs of its aging facilities portfolio, meet facilities requirements related to 

implementation of the Next Generation Air Transportation System 

(NextGen),1

 1 NextGen is a complex undertaking that requires acquiring new integrated air traffic 

control systems; developing new flight procedures, standards, and regulations; and 

creating and maintaining supporting infrastructure to create a more automated aircraftcentered, satellite-based air transportation system. 

and move forward with facility consolidation plans will likely 
Page 2 GAO-13-757 Facilities Condition

be affected by resource constraints as a result of expected lower future 

budgets. The challenges presented by these circumstances relate to 

long-standing problems that we have identified with federal real property, 

an area that we have designated as high-risk.2

Congress mandated in the FAA Modernization and Reform Act of 2012 

that we study the condition of FAA-staffed facilities, including 

administrative and operational facilities, employee occupational safety 

and health issues, and resources allocated to facility maintenance and 

renovation.3 This report follows up an interim report we issued on May 9, 

2013, which discussed our preliminary findings.4

1. What is known about the conditions of FAA-staffed facilities and to 

what extent are the assessment methods and resulting data reliable?

To meet the mandate, 

this report addresses the following questions:

2. What have been the workplace injuries and illnesses reported by FAA 

employees in workers’ compensation claims, and to what extent has 

FAA met its targets for processing claims?

3. To what extent has FAA responded to safety deficiencies identified 

through its inspections and those conducted by the Occupational 

Safety and Health Administration (OSHA)?

4. To what extent are actions FAA has taken to ensure that its facilities 

are in good condition, if any, consistent with leading practices for 

capital-investment decisions?

To determine what is known about the conditions of FAA facilities and the 

extent to which the methods used to make those determinations and the 

resulting data are reliable, we collected condition data from 2010 through 

 2 GAO, High-Risk Series: Federal Real Property, GAO-03-122 (Washington, D.C.: 

January 2003) and GAO, High-Risk Series: An Update, GAO-13-283 (Washington, D.C.: 

February 2013). Our high-risk series identifies areas at high risk because of their greater 

vulnerabilities to waste, fraud, abuse, and mismanagement or major challenges 

associated with their economy, efficiency, or effectiveness. We identified federal real 

property as a high-risk area because of long-standing problems with excess and 

underutilized real property, deteriorating facilities, unreliable real property data, and costly 

space challenges shared by several agencies.

3 FAA Modernization and Reform Act of 2012, Pub. L. No. 112-95, § 610, 126 Stat. 11, 

117 (Feb. 14, 2012). 

4 GAO, Preliminary Results of Work on FAA Facility Conditions and Workplace Safety, 

GAO-13-509R (Washington, D.C.: May 9, 2013).
Page 3 GAO-13-757 Facilities Condition

2012 from FAA and GSA. To assess the reliability of the FAA data we 

reviewed existing documentation, interviewed cognizant agency officials, 

and performed electronic testing for obvious errors in accuracy and 

completeness. To assess the reliability of the GSA data, we reviewed 

existing documentation and interviewed knowledgeable agency officials. 

We found that data in FAA’s agency-wide Real Estate Management 

System (REMS) were not sufficiently reliable for describing facility 

condition, as discussed later in this report. However, we determined that 

data from other sources maintained by FAA organizational components 

with facilities maintenance responsibilities and from GSA were sufficiently 

reliable for this purpose. To determine whether the inspection methods 

used by FAA or GSA to obtain facility condition information were reliable 

for this purpose, we compared those methods with generally accepted 

industry standards and interviewed FAA and GSA facility officials and 

FAA’s engineering consultants. We also interviewed FAA and union 

officials representing major aviation employee groups about facility 

conditions. To observe conditions and speak with knowledgeable staff to 

learn about any facility deficiencies and the projects for fixing them, we 

visited facilities supporting operations and administrative functions in 

each of FAA’s three geographic service areas.5

 5 FAA’s service areas comprise the eastern, central, and western regions of the country.

To determine the most 

common types of workplace injuries and illnesses FAA employees have 

reported, if any, we reviewed FAA and Department of Labor (Labor) 

workers’ compensation data from 2007 through 2012. To determine the 

extent to which FAA has complied with its targets for processing claims, 

we compared actual performance to the targets. To assess the reliability 

of the data, we reviewed existing documentation, interviewed 

knowledgeable agency officials, and performed electronic testing for 

obvious errors in accuracy and completeness. We found the data to be 

sufficiently reliable for the purposes of this report. Because of the 

variability of factors that may contribute to reported injuries and illnesses, 

our study does not attempt to link workers’ compensation claims to facility 

conditions. To determine how FAA has responded to any safety 

deficiencies identified through inspections of its facilities, we reviewed 

FAA and OSHA inspection reports and documents pertaining to how FAA 

has addressed deficiencies. Regarding actions FAA has taken to ensure 

that its facilities are in good and safe condition, consistent with leading 

practices, we reviewed FAA’s process for making capital decisions and 

compared it to our and the Office of Management and Budget’s (OMB) 
Page 4 GAO-13-757 Facilities Condition

leading practices.6

We conducted this performance audit from July 2012 to September 2013 

in accordance with generally accepted government auditing standards. 

Those standards require that we plan and perform the audit to obtain 

sufficient, appropriate evidence to provide a reasonable basis for our 

findings and conclusions based on our audit objectives. We believe that 

the evidence we obtained provides a reasonable basis for our findings 

and conclusions based on our audit objectives.

Appendix I has a more detailed discussion of our 

scope and methodology.

Responsibility for maintaining the approximately 1,230 staffed FAA 

facilities—ranging from administrative buildings to operations buildings 

such as air traffic control towers—is distributed among FAA, GSA, and 

other entities, as shown in table 1.7

 6 GAO, Executive Guide: Leading Practices in Capital Decision-Making. 

Within FAA, several components hold 

responsibility for facilities maintenance, including the Air Traffic 

Organization (ATO), Mike Monroney Aeronautical Center (Aeronautical 

Center), and William J. Hughes Technical Center (Technical Center). 

ATO maintains facilities supporting air traffic control operations at multiple 

locations across the country and overseas. These include en-route traffic 

control facilities that control high-altitude air traffic and terminal facilities 

that control low altitude air traffic. FAA’s Aeronautical Center and 

Technical Center maintain facilities on their respective campuses in 

Oklahoma City and Atlantic City that provide research and training 

functions. GSA maintains some of FAA’s administrative facilities including 

FAA’s headquarters in Washington, D.C., and regional offices around the 

country. FAA also occupies several hundred facilities across the country 

GAO/AIMD-99-32

(Washington, D.C.: December 1998); OMB, Capital Programming Guide, Supplement to 

Office of Management and Budget Circular A-11: Planning, Budgeting, and Acquisition of 

Capital Assets (July 2012).

7 The FAA Unstaffed Infrastructure Sustainment program manages approximately 30,000 

unstaffed facilities that house, protect, and support National Airspace System (NAS) 

communications, navigation, surveillance, weather, and other air traffic control equipment. 

This study is limited to FAA-staffed facilities maintained by FAA and GSA. For more 

information on unstaffed facilities, please see GAO, National Airspace System: Improved 

Budget Process Could Help FAA Better Determine Future Operations and Maintenance 

Priorities, GAO-13-693 (Washington, D.C.: Aug. 22, 2013). 

Background

Facility Maintenance 

Responsibility
Page 5 GAO-13-757 Facilities Condition

through leases or other types of agreements under which the (nonfederal) owner is responsible for maintenance. These include air traffic 

control towers and administrative facilities that serve a variety of 

functions.8

Table 1: Maintenance Responsibilities for FAA’s Staffed Facilities, 2013

Facility Description Responsible entity (number of facilities) Total

FAA GSA Other

(including

non-federal)

En-route Traffic Control Facilities 23 - - 23

Terminal facility sites, including 

Air Traffic Control Towers and 

Terminal Radar Approach Control 

(TRACON) facilities 402 - 137 539

FAA Mike Monroney Aeronautical 

Center

a

37 b - 23 60

FAA William J. Hughes Technical 

Center 43 - - 43

Administrative/Other - 8 560c 568

Total 505 8 720 1233

Source: GAO analysis of FAA and GSA data.

Note: FAA maintains some facilities that are not federally owned. For example, under the terms of 

some lease agreements, FAA maintains terminal facilities that are owned by non-federal entities such 

as airport authorities.

a Some of the terminal facility sites contain more than one facility. According to FAA facility data, 

there are 543 facilities at these sites.

b

c This includes 33 facilities that GSA leases on behalf of FAA for FAA staff; the property owners are 

responsible for their maintenance.

In 2013, Aeronautical Center staff occupy 60 facilities that include facilities that are either federally 

owned or leased from the Oklahoma City Airport Trust, which has primary responsibility for their 

maintenance. The Aeronautical Center also has an additional 68 federally maintained and leased 

facilities that are considered unstaffed.

 8 Examples of FAA’s administrative offices include its Certificate Management Office 

(CMO), Flight Standards District Office (FSDO), and Manufacturing Inspection District 

Office (MIDO). FAA’s CMO is responsible for the certification, surveillance, and inspection 

of major air carriers and Flight Safety International’s part 142 Training Centers; its FSDO 

responsibilities include airmen certification (licensing) for pilots, mechanics, repairmen, 

dispatchers, and parachute riggers; and the responsibilities of its MIDOs include 

airworthiness certification and the oversight of Manufacturing Designees. 
Page 6 GAO-13-757 Facilities Condition

GSA’s and FAA’s internal organizational components responsible for 

facility maintenance collect information on the condition of their respective 

facility portfolios. This generally includes information on the Facility 

Condition Index (FCI)9 and deferred maintenance10—two widely used 

benchmarks to determine the relative condition of public and private 

facilities. However, because of the variation in methods used to determine 

condition, the condition data for one type of facility may not be 

comparable to that for another type of facility. FAA also maintains an 

agency-wide Real Estate Management System (REMS) to collect 

information, including FCI data, on facilities in its inventory. FAA uses 

REMS for reporting required information to the Federal Real Property 

Profile (FRPP).11

Funding for facilities modernization, improvement, and replacement 

projects derives from FAA’s Facilities and Equipment account.12

Two agencies within Labor administer programs related to safety and 

health issues in federal facilities: OSHA, which oversees compliance with 

occupational safety and health standards, and the Office of Workers’ 

Compensation Programs (OWCP), which oversees certain programs to 

compensate employees for wages lost as a result of employment-related 

The 

funding in this account is tied to the annually updated Capital Investment 

Plan, or CIP. This plan is to identify planned capital investments for the 

next 5 years consistent with the amount requested in FAA’s annual 

budget submission.

 9 As a formula, FCI is the value of the maintenance, repair, and replacement deficiencies 

of a facility divided by its current replacement value. The resulting fraction is then 

subtracted from 1 to express FCI as a percentage. Facilities can be grouped according to 

FCI values. ATO, for example, defines a facility with an FCI above 95 percent as in “good”

condition, 90 to 95 percent to be in “fair” condition, and below 90 percent to be in “poor”

condition.

10 For its en-route and terminal facilities, FAA defines deferred maintenance as the cost of 

rebuilding or replacing components whose service life has exceeded their scheduled 

lifetime as of the forecast year. FAA does not include preventative maintenance and minor 

repairs in its deferred maintenance calculations.

11 FRPP is the inventory system for the federal real property portfolio. FRPP, which is 

overseen by OMB, includes data elements that agencies are mandated to report annually, 

including performance measures on asset utilization, condition, mission dependency, and 

operating cost.

12 Two budget accounts provide the principal source of funding for FAA facilities. The 

Facilities and Equipment account funds major modernization and improvement projects 

while the Operations account funds routine maintenance and repairs.

FAA Employees’ Safety 

and Health
Page 7 GAO-13-757 Facilities Condition

injuries or illnesses. OSHA sets and enforces workplace standards 

affecting FAA facilities. As part of its enforcement efforts, OSHA conducts 

programmed and unprogrammed inspections of worksites to ensure 

compliance with its safety and health standards.13 Among other things, 

OWCP adjudicates federal employees’ claims for compensation resulting 

from employment-related injuries and illnesses. FAA staff who sustain 

employment-related injuries and illnesses may file a workers’ 

compensation claim with FAA for subsequent transmittal to OWCP.14

In addition, as required by law, FAA administers an environmental and

occupational safety and health (EOSH) program that includes inspections 

aimed at preventing workplace injuries.15 Under its EOSH program, FAA 

annually inspects each of its staffed facilities and maintains inspection 

results in a central database. Also, under its EOSH program, FAA 

established Occupational Safety, Health, and Environmental Compliance 

Committees (OSHECCOM) to provide a method for employees to use 

their knowledge of workplace operations to assist agency management in 

improving policies, conditions, and practices concerning safety and health 

matters in agency workplaces.

 13 OSHA’s programmed inspections are scheduled investigations that target specific 

worksite hazards or high-hazard industries and worksites. OSHA’s unprogrammed 

inspections are conducted in response to imminent danger, fatalities or catastrophes, 

complaints, referrals, and as follow-up and monitoring of prior inspections.

14 For claims it approves, OWCP bases the benefits on an employee’s wages at time of 

injury, the date the disability began or the date the disability recurred, his or her ability to 

work after the injury, and whether he or she has eligible dependents. OWCP charges 

agencies for the benefits provided to their injured employees. These agencies 

subsequently reimburse Labor’s Employees’ Compensation Fund from their next annual 

appropriation. Workers’ compensation benefits paid to beneficiaries are adjusted for 

inflation and are not taxed or subject to age restrictions.

15 See 29 U.S.C. § 668, 29 C.F.R. pt. 1960, and Exec. Order No. 12196, Occupational 

Safety and Health Programs for Federal Employees, 45 Fed. Reg. 12769 (Feb. 27, 1980).
Page 8 GAO-13-757 Facilities Condition

According to data available for the federally maintained facilities occupied 

by FAA staff, facilities are generally in “good” to “fair” condition based on 

their FCIs.16 This information results from the condition assessment 

processes and data sources used by each FAA organizational component 

that has facility maintenance responsibility as well as from GSA.17

• ATO uses a technical-consulting firm to annually inspect a portion of 

en-route and terminal facilities. ATO’s consultant annually produces 

“roll-up” reports that provide condition information for facilities that 

have been inspected during the current year as well as during the 

preceding 5-year period.

Specifically:

18

 16 See footnote 9.

For terminal facilities not inspected over 

this time period, ATO’s consultant estimates their condition by using 

17 As discussed below, Technical Center managers use a process that assesses the 

conditions of a facility’s components such as structural, electrical, and mechanical 

systems. This process does not yield an FCI for each facility but rather provides 

component-specific measures of condition. 

18 FAA’s consultant inspects each en-route facility approximately once every 4 to 5 years, 

and “roll-up” reports for these facilities contain actual inspection results for each of the 23 

facilities. For terminal facilities, roll-up reports contain actual inspection results from 

facilities inspected over the most recent 6-year period. FAA’s most recent terminal facility 

roll-up report, for example, contains information from 128 facility sites inspected from 

January 2007 through December 2012.

FAA-Staffed Facilities 

Are Generally in 

“Good” to “Fair”

Condition, but 

Opportunities Exist to 

Improve Assessment 

Methods and 

Condition Information

Most Federally Maintained 

Facilities Occupied by FAA 

Employees Are in “Good”

to “Fair” Condition
Page 9 GAO-13-757 Facilities Condition

the condition data from inspected facilities; these estimates are 

contained in the annual terminal facilities roll-up report.19

• Aeronautical Center managers use a technical-consulting firm to 

inspect their federally maintained facilities on a biennial basis. 

Aeronautical Center managers use condition data obtained through 

these inspections and update them between inspection cycles to 

reflect repairs or improvements made to those facilities.

• Technical Center managers used a technical contractor to inspect 

most of their federally maintained facilities in 2007 and 2008.20

Technical Center managers use condition data derived from these 

inspections to determine what improvements are needed.

• GSA uses a standardized physical condition survey process 

administered by its on-site staff to biennially assess the condition of 

the facilities it maintains. GSA manages a database containing 

information derived from these surveys.

Because of variations in the methods used to determine condition, the 

condition data for one type of facility may not be comparable to that for 

another type of facility. Our analysis of condition by facility type is 

presented below.

According to ATO’s most recent roll-up reports

• 23 en-route air traffic control centers are generally in “fair” condition 

having an aggregated FCI of 93.5 percent,21 with deferred 

maintenance totaling approximately $98 million and replacement 

values totaling about $1.5 billion.

 19 FAA’s consultant develops a statistical model based on data obtained from the 

inspected facilities to estimate the condition of facilities that have not been inspected. The 

model uses age to estimate the FCI and deferred maintenance of each facility not 

inspected.

20 The inspection covered 34 of the 43 federally maintained staffed facilities at the 

Technical Center. Technical Center managers indicated that they intend to award a new 

contract by early fiscal year 2014 to inspect the 9 facilities not previously inspected in 

2014. 

21 See footnote 9.

En-route Air Traffic Control 

Centers and Terminal Facilities
Page 10 GAO-13-757 Facilities Condition

• 134 terminal facilities—the subset of terminal facilities that have been 

inspected—are at the transition from “good” to “fair” condition having 

an aggregated FCI of 94.9 percent, with deferred maintenance 

totaling about $82 million and replacement values totaling about $1.6 

billion. 22

• 409 terminal facilities—the subset of terminal facilities that have not 

been inspected—have estimated FCI and deferred maintenance 

values. Because FAA’s estimates for these uninspected facilities have 

substantial errors, we do not present condition data for them. We 

discuss in greater detail below and in appendix II the imprecision of 

FAA’s estimating method and alternatives for improving the accuracy 

of its estimates.

Based on our interviews with ATO and its technical consultant, we found 

the inspection and its related reporting process results are reliable 

indicators of the condition of inspected facilities based on generally 

accepted industry standards. However, as we explain below, limitations in 

ATO’s process for estimating the condition of terminal facilities that have 

not been inspected may result in estimates that overstate or understate 

actual conditions. Moreover, based on our discussions with ATO and its 

technical consultant, we learned that condition data prior to 2010 were 

obtained using a different method than currently used. As a result, we 

determined that year-to-year comparison of condition data was 

appropriate only for data for inspected facilities from 2010 through 2012. 

Table 2 shows aggregate FCI and deferred maintenance values for enroute air traffic control centers and terminal facilities over this time period.

 22 If seismic codes and standards deficiencies are included, the aggregated FCI for the 

128 sites is 87.9 percent, or “poor” condition.
Page 11 GAO-13-757 Facilities Condition

Table 2: Aggregate FCI and Deferred Maintenance Values for En-route Air Traffic 

Control Centers and Inspected Terminal Facilities, 2010 through 2012 (Dollars in 

Millions)

Facility 

type 2010 2011 2012

FCI 

Deferred 

maintenance FCI

Deferred 

maintenance FCI

Deferred 

maintenance

En-route

centers 93.7% $91 93.7% $94 93.5% $98

Inspected 

terminal 

facilities 95.2 a 61.8 95.5 65.2 94.9 81.9

Source: National Roll-Up Reports for En-route Facilities and Final MARS Roll-Up Reports for ATCT-TRACON Sites, FAA.

Notes: Data for En-route Centers are based on the fiscal year while data for terminal facilities are 

based on the calendar year. 

The aggregate FCI is the summed deferred maintenance values divided by the summed replacement 

values, subtracted from 1. The aggregate deferred maintenance values represent the summed 

deferred maintenance amounts across the relevant subset of facilities.

a

The data shown are for only those terminal facilities that have been inspected and exclude 

deficiencies resulting from seismic, code, and standards assessments. For 2010, there were 114 

inspected terminal facilities; for 2011, there were 121; and for 2012, there were 134.

According to fiscal year 2010 data, the aggregated FCI of 110 

Aeronautical Center facilities is 95.2 percent, or “good” condition, based 

on deferred maintenance totaling about $6.5 million and replacement 

values totaling about $135 million.23

The Technical Center’s inspection process does not yield facility-level 

condition data such as an FCI. Rather, the process assesses the 

conditions of the components—such as structural, electrical, and 

heating/cooling systems—that comprise each facility. Because available 

data for Technical Center facilities does not reflect facility-level conditions 

Based on interviews with 

Aeronautical Center managers, we found the inspection method followed 

generally accepted industry standards and its related reporting process 

results and are reliable facility condition indicators.

 23 This includes both staffed and unstaffed facilities. According to Aeronautical Center 

officials, unstaffed facilities include guard sheds, shelters for NAS equipment, and other 

services such as Digital Remote Switching. Further, this deferred-maintenance estimate 

does not include costs for design services, demolition and restoration of architectural 

finishes, staging, moving services, and other expenses related to completion of the 

associated maintenance and repair work.

Mike Monroney Aeronautical 

Center Facilities

William J. Hughes Technical 

Center Facilities
Page 12 GAO-13-757 Facilities Condition

similar to what we reported for other facility types, we do not present them 

in this report.

According to GSA data, the 8 staffed facilities it maintains for FAA have 

FCIs ranging from 95 percent (“good” condition) to 46 percent (“poor”

condition).24 GSA-maintained facilities where FAA is the principal 

occupant are the Hawthorne Federal Building (46.0 percent FCI), Orville 

Wright Building (82.0 percent FCI), and Wilbur Wright Building (90.0 

percent FCI).25 We found the facilities condition data for the FAA facilities 

that GSA maintains to be reliable indicators of these facilities.26 We also 

observed that GSA uses a different convention than FAA in categorizing 

facilities based on their FCI values. This results in GSA’s having different 

FCI thresholds than FAA for determining if a facility is in “good,” “fair,” or 

“poor” condition.27

FAA collects information on all facilities in its portfolio (both federally 

owned and leased) and enters the data in REMS, FAA’s repository for its 

entire real-property inventory. Information maintained in REMS includes 

the location, size, age, plant replacement value, operations and 

maintenance costs, repair needs, and FCI data for facilities. REMS is 

overseen by FAA’s Aviation Logistics Organization (ALO), which provides 

guidance for users on updating REMS facilities data. FAA uses REMS for 

reporting required information to the FRPP.28

 24 These facilities include the Orville Wright Building (Washington, D.C.), Wilbur Wright 

Building (Washington, D.C.), Hawthorne Federal Building (Hawthorne, CA), Senator Paul 

Simon Federal Building (Carbondale, IL), Prince J. Kuhio Federal Building and U.S. 

Courthouse (Honolulu, HI), and the Anchorage Federal Building and U.S. Courthouse & 

Annex (Anchorage, AK). FAA may be the sole tenant or part of a multi-tenant occupancy 

of these facilities.

25 FCI information may not reflect current conditions. For example, in January 2013, we 

visited the Hawthorne Federal Building, which is located in FAA’s Western-Pacific Region, 

and saw that the roof had been replaced, which should result in a higher FCI for the facility 

when it is next assessed.

26 Appendix I describes in further detail the steps taken to determine the reliability of the 

data.

27 GSA views an FCI of 90 percent and above as “good” condition, between 70 and 90 

percent as “fair” condition, and less than 70 percent as “poor” condition.

28 See footnote 11.

GSA-Maintained FAA Facilities

REMS Facility Condition 

Data Differ from Those 

Maintained by ATO and the 

Aeronautical Center
Page 13 GAO-13-757 Facilities Condition

We initially assessed REMS data to obtain information on the condition of 

the agency’s facilities but found it was not reliable for this purpose. For 

example, 16.5 percent (141) of the records for non-leased facilities in the 

initial REMS file FAA provided us had missing FCIs or an FCI of zero.29

We also found that the FCI data obtained from ATO and the Aeronautical 

Center did not consistently match FCI data in REMS. REMS uses an FCI 

that was modeled on DOD’s facility-pricing index while ATO’s and the 

Aeronautical Center’s engineering consultants calculate FCIs from actual 

inspections.30

Throughout the course of our review, we brought to ALO’s attention 

deficiencies that we found with REMS, such as facilities with wrong 

addresses, incorrect use status, and erroneous lease costs. Furthermore, 

ALO independently recognized shortcomings with REMS and informed us 

that it has also been trying to correct errors with the data as well as 

address deficiencies we identified.

FAA officials recognized that ATO’s and the Aeronautical 

Center’s FCI data were more robust and indicated that we should use 

their data in lieu of REMS in our assessment of facilities that are 

maintained by FAA. 

31

 29 While FAA is required to maintain information on leased properties in REMS, FCIs are 

not one of the required data elements for these facilities.

For example, Aeronautical Center 

officials told us that whenever they tried to update REMS with their FCI 

data, the updated condition data would revert back to the original REMS 

data after a certain period of time. FAA officials and the consulting firm 

that manages REMS told us that a “business rule” in the programming for 

REMS caused the condition data updates entered by Aeronautical Center 

staff to be overwritten, causing the accurate up-to-date data to be 

replaced by the old data. ALO recently agreed to change this “business 

rule” to prevent updated facility condition data from being overwritten. In 

addition, ALO has taken steps to correct the errors with address, use 

status, and lease data. For example, ALO recently found 13 cases of an 

air traffic control tower noted as “unstaffed” and updated the database to 

show their use as staffed facilities. ALO officials also plan to replace the 

different identifiers currently used in REMS for denoting an air traffic 

control tower with just one primary identifier. ALO officials agreed that 

30 According to FAA officials, the REMS model for estimating FCI incorporates the DOD 

Facilities Pricing Guide in part because FAA has comparable facilities to DOD, such as air 

traffic control towers.

31 In response to our questions about REMS data, FAA sent us revised REMS data sets 

on at least three different occasions. 
Page 14 GAO-13-757 Facilities Condition

REMS data need to be better synchronized with other real property data 

in FAA’s other organizational components. To be better stewards of 

FAA’s real property, on June 24, 2013, FAA chartered a property 

accountability board—a cross-organizational entity that is to continue to 

undertake strategic, management, and operational initiatives to improve 

property management.

We are encouraged with the steps FAA is taking to address the REMS 

deficiencies we identified to ensure a strong data validation and 

correction process, but the extent to which other deficiencies exist is not 

clear as FAA has not comprehensively assessed the quality of REMS 

data and raises questions as to whether the database is a useful tool for 

managing FAA’s facilities portfolio. Federal internal control standards 

state that agencies have relevant, reliable, and timely information for 

decision-making and external-reporting purposes.32 This is enabled by 

sound and consistent data collection practices that ensure data are 

reasonably complete and accurate. OMB also has data quality guidelines 

for ensuring quality in information disseminated by federal agencies.33

Furthermore, leading practices for using information to make capitalinvestment decisions call for a needs assessment that makes use of an 

accurate and up-to-date inventory of assets as well as current information 

on their condition.34 Comprehensively assessing the quality of the REMS 

data, determining if the data are appropriate for their intended use, and 

implementing corrective actions, as needed, to ensure that data are 

sufficiently complete and accurate with data maintained among other FAA 

organizational components would provide FAA with better assurance that 

its source for facilities information agencywide is reliable for making 

informed decisions.

 32GAO, Standards for Internal Control in the Federal Government, GAO/AIMD-00-21.3.1

(Washington, D.C.: November 1999). 

33 Office of Management and Budget, “Guidelines for Ensuring and Maximizing the 

Quality, Objectivity, Utility, and Integrity of Information Disseminated by Federal 

Agencies.” 67 Fed. Reg. 8452 (Feb. 22, 2002). Those guidelines state that, among other 

things, agencies “shall adopt a basic standard of quality (including objectivity, utility, and 

integrity) as a performance goal and should take appropriate steps to incorporate 

information quality criteria into agency information dissemination practices.”

34 See footnote 6. 
Page 15 GAO-13-757 Facilities Condition

As indicated above, ATO uses a statistical method to estimate the 

condition of most terminal facilities; however, the limitations of this 

method produce estimates with substantial error and uncertainty. ATO 

has current inspection data for approximately one quarter of all terminal

facilities (based on a 6-year rolling count of inspected facilities35

The following example derived from this roll-up report illustrates the 

limitations of using facility age as the sole determinant in estimating FCI 

and deferred maintenance. In the 2012 roll-up report, eight air traffic 

control towers, each 17 years old, were identified as having the same FCI 

and deferred maintenance amount, about 96.5 percent and around 

$215,000 respectively, as estimated based on age (see fig. 1). However, 

given differences in their locations, sizes, number of flight operations 

managed, and physical components, actual conditions at each are likely 

different. For example, two of these towers are located at two of the 

busiest airports in the country, Chicago, IL, and Los Angeles, CA. These 

towers are larger and experience more wear than other towers as a result 

of comparatively greater use by controllers. During our visit to the Los 

Angeles tower, officials showed us the single elevator that services the 

tower’s cab and described its maintenance issues.

) and 

estimates the condition of the remaining facilities that have not been 

inspected. ATO’s consulting firm annually develops a statistical model 

based on data obtained from the inspected facilities to estimate the 

condition of facilities that have not been inspected. In particular, the 

model uses facility age to estimate the FCI and deferred maintenance of 

each facility not inspected. In 2012, for example, ATO’s consultant 

developed a statistical model based on inspection results of 134 

inspected facilities to estimate the FCI and deferred maintenance at 409 

facilities not inspected. ATO’s 2012 terminal facilities “roll-up” report 

presents condition information for these facilities.

36 These officials 

noted, at the time of our visit in January 2013, that this elevator had 

experienced 17 outages since May 2012 and would cost about $500,000 

to repair.37

 35 See footnote 18.

36 The cab is the elevated component of the air traffic control tower where controllers 

direct ground traffic, takeoffs, and landings.

37 According to officials at the tower, the elevator will undergo repairs in September 2013, 

partially funded by resources diverted from a repair project at another facility. 

FAA’s Method of Assessing 

the Condition of 

Uninspected Terminal 

Facilities Produces Error 

and Uncertainty
Page 16 GAO-13-757 Facilities Condition

Figure 1: Eight FAA Air Traffic Control Towers Reported to Have the Same FCI and Deferred Maintenance Amount 

To quantify the accuracy of the methods ATO’s consultant used to 

estimate the FCIs and deferred maintenance of uninspected terminal 

facilities shown in the 2012 roll-up report, we compared FCI and deferred 
Page 17 GAO-13-757 Facilities Condition

maintenance data derived from actual inspection of 134 facilities38

As another approach to testing the accuracy of ATO’s statistical model for 

estimating FCI and deferred maintenance, and assessing alternatives for 

improving the model, we used data presented in the 2010 roll-up report 

as described below. Appendix II presents a more detailed description of 

our analysis.

to what 

their estimated FCI and deferred maintenance values would be using the 

statistical model. In reference to FAA’s general categorization of facilities 

in “good”, “fair”, or “poor” condition based on their FCI values, we found 

that 41 percent of the inspected facilities would have been reclassified 

using estimated rather than actual FCI values. In particular, the statistical 

model classified 32 of the 134 facilities (24 percent) in a better condition 

category than actual inspection data showed, and it classified 23 of 134 

facilities (17 percent) in a worse condition category than actual inspection 

data showed. For deferred maintenance, we found that, in 2012, 94 

percent of facilities had estimated deferred maintenance values that 

differed by greater than 10 percent from actual values.

• Accuracy of FCI estimates. To assess the accuracy of FCI estimates, 

we compared actual FCI results (based on inspections) to the model’s 

predictions for the same facilities. The goal was to calculate the 

uncertainty of the predicted FCIs, as calculated from the ATO model. 

We found that ATO’s estimates were not highly precise. The model 

estimated that if ATO measured actual FCIs for a new sample of 

facilities, the actual FCIs would vary by an average of plus or minus 

3.4 percentage points in 95 percent of the new samples. That is a 

moderately large error, given that the middle 50 percent of actual FCIs 

ranged from 90.9 to 96.6 percentage points. In other words, the 

margin of error of the estimates was almost as large as the range of 

the actual FCIs.

• Accuracy of deferred maintenance estimates. To assess the accuracy 

of deferred maintenance estimates, we compared actual deferred 

maintenance results (based on inspections) to the model’s predictions 

for the same facilities. Similar to our findings on FCI estimates, we 

found that ATO’s estimates for deferred maintenance were not highly 

precise. On average, the model’s estimates varied from the actual 

 38 While there are 128 facility sites inspected, some of those sites have more than one 

facility or tower. Condition data were obtained at 134 facilities within these 128 sites.
Page 18 GAO-13-757 Facilities Condition

deferred maintenance by $606,862. This is a moderately large error, 

given that the middle 50 percent of actual deferred maintenance 

values ranged from $231,420 to $663,944 in this time period.

Our analysis shows that although FCI and deferred maintenance are 

correlated with age, the strength of the relationship is not strong enough 

to produce highly precise estimates of FCI and deferred maintenance for 

facilities that are not inspected. As a result, the true condition of the 

uninspected facilities is less precise and certain than FAA’s roll-up reports 

suggest. Based on our analysis of FAA’s data, we determined that 

increasing the number of variables in FAA’s estimation method could 

potentially improve its accuracy. For example, we found that incorporating 

facility replacement value39

Table 3: Comparison of Results from FAA and GAO Models for Estimating Deferred 

Maintenance at Selected Terminal Facilities (Dollars in Thousands)

into the model for estimating deferred 

maintenance significantly reduced the error and uncertainty of the 

estimates. Table 3 illustrates the difference in accuracy between the ATO 

consultant’s use of age as the only factor to predict deferred maintenance 

and our use of age and facility replacement value. On average, our model 

predicted deferred maintenance with 39 percent less error than ATO’s 

current approach.

Facility

Facility 

age 

(years)

Facility 

replacement 

value 

Deferred 

maintenance 

– actual

Deferred 

maintenance 

– FAA 

estimate a

Deferred 

maintenance 

– GAO 

estimate b

Dallas -

Ft Worth 

TRACON 

(Texas)

c

36 $42,112 $2,893 $524 $3,143

Greensboro 

Tower (North 

Carolina) 36 7,506 1,173 524 592

Teterboro 

Tower (New 

Jersey) 36 4.215 289 524 349

Woodring 

Tower 

(Oklahoma) 36 3,129 150 524 269

 39 Facility replacement value is the total expenditure required to replace a facility, inclusive 

of construction, design, and project management and administrative costs.
Page 19 GAO-13-757 Facilities Condition

Facility

Facility 

age 

(years)

Facility 

replacement 

value 

Deferred 

maintenance 

– actual

Deferred 

maintenance 

– FAA 

estimate a

Deferred 

maintenance 

– GAO 

estimate b

Yakima Tower 

(Washington) 

c

36 3,487 295 524 296

Source: GAO analysis

a

Actual deferred maintenance as shown in FAA’s 2010 terminal facility roll-up report. b

Estimate based on FAA consultant’s model using facility age to predict deferred maintenance.

c

For its part, ATO’s consultant has documented in the roll-up reports the 

limitations of its model to estimate FCI and deferred maintenance and has 

recommended improvements, such as using facility size as a variable in 

the model. As indicated by our analysis, increasing the number of 

variables in the method for estimating FCI and deferred maintenance 

could potentially improve the FCI’s accuracy, because the method would 

include other factors that are correlated with condition, such as usage and 

weather conditions. In addition, assessing and reporting the prediction 

error associated with any statistical estimate, regardless of the estimation 

method used, is useful in quantifying the degree to which the estimate

varies from actual conditions. Also, inspecting the condition of a 

probability sample of terminal facilities, either as a supplement or 

alternative to FAA’s current approach, may help ensure that FCI 

estimates accurately represent the population, particularly for reporting 

average and total condition across facilities. Having accurate and reliable 

facility condition data allows management to have a clear picture of repair 

needs that may affect future budget requests.

Estimate based on GAO model using facility age and facility replacement value to predict deferred 

maintenance.

40

 40 GAO, Federal Buildings Fund: Improved Transparency and Long-term Plan Needed to 

Clarify Capital Funding Priorities, GAO-12-646 (Washington, D.C.: July 12, 2012).
Page 20 GAO-13-757 Facilities Condition

Workers’ compensation claims filed by FAA employees and accepted by 

OWCP from 2007 through 201241 indicate that the five most common 

types of injuries and illnesses sustained by FAA employees ranged from 

mental, emotional, or nervous conditions to different types of orthopedic 

injuries (see table 4). According to FAA officials, orthopedic injuries 

represent the most frequent types of injuries filed by FAA employees and 

accepted by OWCP. These claims cite various causes of reported injuries 

and illnesses including falls, handling tools and materials, fume inhalation, 

and vehicle accidents. Workers’ compensation claims data cannot be 

linked to facility conditions because of the variability of factors contributing 

to reported injuries and illnesses.

 41 OWCP data for 2012 are from January to September.

While the Number of 

Injuries and Illnesses 

Resulting in FAA’s 

Workers’ 

Compensation Claims 

Has Steadily 

Decreased from 2007 

Through 2011, FAA 

Has Not Always Met 

Its Goals for 

Processing Claims

The Most Common Types 

of Injuries and Illnesses 

Claimed Include 

Orthopedic and Mental, 

Emotional, or Nervous 

Conditions
Page 21 GAO-13-757 Facilities Condition

Table 4: Top Five Types of Injuries or Illnesses Claims Filed by FAA Employees and 

Accepted by OWCP, 2007 to 2012

Nature of injury Number of Claims

Mental, emotional, or nervous condition 928

Back sprain/strain or back pain 826 a

Sprain/strain of ligament, muscle, tendon (not back) 700 a

Pain, swelling, redness, stiffness (not in joint) 615 a

Joint pain/swelling/stiffness/rednessa 472

Source: GAO analysis of Labor data.

Note: Data are based on the date of injury indicated on certified workers’ compensation claims filed 

by FAA employees and accepted by OWCP. Data for 2012 are from January through September.

a

FAA considers these injuries to be orthopedic injuries.

The number of workers’ compensation claims filed by FAA employees 

and accepted by OWCP has steadily decreased since 2007.42 According 

to OWCP data, in 2011, 907 injuries resulted in workers’ compensation 

claims filed by FAA employees that were accepted by OWCP—a 

decrease of 32 percent since 2007 (see fig. 2).43

 42 The Federal Employees’ Compensation Act provides that a claim for compensation 

must be filed within 3 years of the date of injury. For a traumatic injury, the statutory time 

limitation begins to run from the date of injury. For a latent condition, it begins to run when 

an injured employee with a compensable disability becomes aware, or reasonably should 

have been aware, of a possible relationship between the medical condition and the 

employment.

Over the same time 

period, the number of permanent FAA employees increased from 44,423 

in 2007 to 47,242 in 2011. The ratio of the number of FAA employees to 

the number of workers’ compensation claims filed by an FAA employee 

and accepted by OWCP has increased from 33:1 in 2007 to 52:1 in 2011 

(see table 5).

43 For this report, we are using the date of injury to track the number of new workers’

compensation claims filed by FAA employees and accepted by OWCP each year. These 

figures do not include workers’ compensation claims that were rejected by OWCP or 

injuries for which an employee did not file a claim. 

The Number of Workers’ 

Compensation Claims 

Filed by FAA Employees 

and Accepted by OWCP 

Decreased from 2007 

through 2011
Page 22 GAO-13-757 Facilities Condition

Figure 2: Number of Workers’ Compensation Claims of FAA Employees Accepted 

by OWCP, 2007 to 2012

Note: Data are based on the date of injury indicated on workers’ compensation claims filed by FAA 

employees and accepted by OWCP.

a Data for 2012 are from January through September.

Table 5: Ratio of FAA Employees to Number of Claims Filed by FAA Employees and 

Accepted by OWCP, 2007 through 2011

2007 2008 2009 2010 2011

Claims 1,336 1,118 1,045 949 907

Number of FAA employees 44,423 45,272 47,020 47,456 47,242

Employees per claim 33 :1 40 :1 45 :1 50 :1 52 :1

Source: GAO analysis of FAA and DOL OWCP data.

FAA’s total annual workers’ compensation claim payments remained 

relatively constant during this period, ranging from $87 million to $91 

million (see table 6). According to FAA, the annual payments have 

remained constant due to the large number of claims it must pay out that 

were accepted from previous years. For example, in fiscal year 2012, 

FAA paid 2,885 workers’ compensation claims at a total cost of $95 

million. Of those claims, 766 were accepted from 1961 to 1983 and 

accounted for $46.7 million of the 2012 costs. An FAA official attributed 

the constant annual costs to the rising costs of medical care and the 
Page 23 GAO-13-757 Facilities Condition

annual cost of living adjustment to the level of compensation being 

provided to FAA claimants.

Table 6: FAA’s Total Annual Workers’ Compensation Claims Payments, 2007 

through 2012

2007 2008 2009 2010 2011 2012

Annual Payments 

(millions of dollars) $87.0 $90.9 $92.5 $91.0 $90.6 $94.9

Source: FAA data.

FAA tracks its performance in processing employees’ workers’ 

compensation claims on an annual basis. According to FAA, it is required 

to process an employee’s workers’ compensation claim (form CA-1 or 

CA-2) internally and send it to Labor’s OWCP for evaluation within 10 

business days or 14 calendar days. FAA typically sets an annual 

performance target relative to this requirement. From 2007 through 2012, 

FAA has both exceeded and missed the target twice. FAA did not set a 

target for 2 of the 6 years. See table 7 for the annual targets and year end 

performance.

Table 7: FAA CA-1 and CA-2 Filing Timeliness: Percentage within 14 Days, Fiscal 

Year 2007 through 2012

2007 2008 2009 2010 2011 2012

Target N/A 65.3 68.6 N/A 86.9 89.5

Year-end performance 77.1 83.0 84.4 85.0 85.0 87.3

Source: Labor data.

FAA also measures the performance of its workers’ compensation 

program by comparing changes in the percentage of its workers’ 

compensation costs against similar changes government-wide. From 

fiscal year 2007 to 2012, FAA’s annual workers’ compensation costs 

increased 9 percent ($87.0 million to $94.9 million) while the governmentwide average increased 21 percent ($2.49 billion to $3.01 billion).

Each year, FAA also estimates the amount of compensation payments 

and continuation of pay avoided when FAA either challenges a claim of 

questionable veracity and it is subsequently denied by OWCP, or an 

employee returns to duty following a disabling work injury as a result of 

FAA case management actions. From 2007 to 2012, FAA’s annual 

FAA Uses Various 

Measures to Track the 

Performance of Its 

Workers’ Compensation 

Program
Page 24 GAO-13-757 Facilities Condition

compensation payments and continuation of pay avoided estimates for 

workers’ compensation payments ranged from $8 million to $26 million.

FAA has mechanisms to identify safety deficiencies at FAA facilities. For 

example, FAA annually conducts a safety and health inspection, as 

required by regulation,44 at each of its staffed facilities45 under its

Environmental and Occupational Safety and Health (EOSH) program.46

As of March 15, 2013, FAA was tracking 123,368 separate hazards in 

WIT, with over 96 percent of those hazards abated and 4 percent open 

since WIT was implemented in October 2007. FAA officials stated that 

The goals of FAA’s EOSH program are to (1) ensure a safe working 

environment, (2) establish a uniform, national workplace inspections 

process to identify hazards with the potential to cause injury, illness, or 

death, and (3) monitor and evaluate FAA’s compliance with workplace 

inspection and hazard abatement requirements, measured against 

applicable federal, state, and local regulations. According to FAA, trained 

FAA employees or contractors perform the annual EOSH inspections. 

Before inspecting a facility, inspectors must review the injury/illness 

records, previous inspection reports, open findings, reports of unsafe and 

unhealthful working conditions, and employee complaints. After 

inspecting a facility, according to FAA, inspectors brief the facility’s 

managers and then enter the results in FAA’s Workplace Inspection Tool 

(WIT), which is a central database that management uses to track and 

ensure that identified safety and health hazards are mitigated.

 44 OSHA regulations require that all areas and operations of each workplace, including 

office operations, be inspected at least annually. 29 C.F.R. § 1960.25(c). 

45 FAA defines a “facility” as a physical location where agency work or operations are 

routinely performed and include offices, buildings, structures, work areas, equipment, and 

outside grounds associated with the facility.

46 According to FAA, its occupational safety and health inspection program includes 

environmental aspects. 

FAA Has Taken Steps 

to Identify and Abate 

Workplace Hazards

FAA’s EOSH Program 

Includes Steps to Identify 

and Manage the Mitigation 

of Hazards
Page 25 GAO-13-757 Facilities Condition

many of the open hazards are infrastructure-based improvements that will 

require significant funding to abate. For example, FAA reported that a $2 

million infrastructure-based improvement is needed to abate extensive 

water intrusion and mold, which has caused the closure of three levels of 

the air traffic control tower at the San Juan, Puerto Rico, airport. The WIT 

was initially used by ATO but was recently expanded to the rest of FAA 

because of its effectiveness, according to FAA.

To better understand and improve its EOSH program, FAA commissioned 

a consultant’s study, issued in December 2012, to evaluate the EOSH 

programs across the agency. The report concluded that ATO has 

established the most comprehensive program within the FAA. However, 

the report also noted that 8 out of 11 organizational components 

evaluated were either unaware of their responsibilities or had undertaken 

little or no action to implement a complaint program. According to FAA 

officials, ATO’s EOSH program will absorb the EOSH programs of the 

other organizational components to mitigate the issues described in the 

report and ensure a uniform approach to workplace safety.

In June 2008, FAA established an Occupational Safety, Health, and 

Environmental Compliance Committee (OSHECCOM) at the National, 

Region, Center, and field levels.47 The committees were created to 

provide a method for employees to use their knowledge of workplace 

operations to assist agency management in improving polices, conditions, 

and practices. The role of OSHECCOM is to assist FAA’s organizational 

components in maintaining an open channel of communication between 

employees and management concerning safety and health matters in the 

workplace.48

 47 In March 1996, FAA originally established an OSHECCOM and reemphasized that 

effort in June 2008 with a revised charter.

48 Specifically, the OSHECCOM works to (1) establish a culture within FAA that facilitates 

an effective occupational safety, health, and environmental program; (2) improve intraagency cooperation by establishing communication across the organizational components 

and promote a comprehensive occupational safety, health, and environmental program 

that can be implemented at all operational levels; (3) provide an open line of 

communication between management and nonmanagement employees regarding EOSH 

related matters; (4) monitor, assist, and support FAA’s EOSH program; and (5) create a 

forum to address and discuss EOSH issues without fear of reprisal. 

FAA Contracted for an 

Evaluation of EOSH 

Programs

FAA Established Safety 

Committees
Page 26 GAO-13-757 Facilities Condition

According to FAA, the national OSHECCOM has improved the EOSH 

program. For example, the national OSHECCOM implemented a 

cardiopulmonary resuscitation and automated external defibrillator 

program that trained thousands of FAA employees to render emergency 

medical care to individuals in FAA facilities. According to FAA officials, 

FAA employees used the training at an airline training facility in Texas to 

save the life of a pilot who was in cardiac arrest. FAA’s employee union 

organizations stated that the OSHECCOMs, on the national level, have 

improved the level of communication between FAA and employees and 

that they expect it to continue to improve as the EOSH programs from the 

rest of FAA are moved under ATO’s EOSH program. In addition, 

according to union officials we met with at the Aeronautical Center, the 

center’s OSHECCOM was able to identify and mitigate serious pedestrian 

safety issues on the center’s campus.

FAA employees may also report any hazards they identify to FAA 

managers at their facility or, as applicable, to their union representative or 

OSHA. According to FAA, facility managers then work to abate the 

hazard. In addition, FAA has agreements with employee union 

organizations to report safety concerns. Specifically, the Air Traffic Safety 

Action Program is an agreement between FAA and the National Air 

Traffic Controllers Association and the National Association of 

Government Employees that is designed to foster a voluntary, 

cooperative, nonpunitive environment for FAA air traffic employees to 

openly report safety concerns. Similarly, the Technical Operations Safety 

Action Program (T-SAP) is an agreement between FAA and the 

Professional Aviation Safety Specialists (PASS) that allows technicians 

represented by PASS and other non-bargaining unit Technical Operations 

employees the opportunity to report potential safety hazards voluntarily 

and confidentially. T-SAP is still a demonstration program, only available 

to employees in the Central Service Area, but FAA plans to expand this 

program.

OSHA conducted inspections at 153 FAA facilities from 2007 to 2012. Of 

these inspections, 57 were unprogrammed, including those originating 

from employee complaints such as unsafe egress. The 96 other 

inspections were programmed inspections that targeted specific worksite 

hazards or high-hazard worksites. OSHA began one such targeted 

inspection program to focus on concerns related to egress and fire safety 

at federally owned air traffic control towers operated by FAA. Under 

OSHA’s Airport Traffic Control Tower Monitoring Inspection Program 

(AIRTRAF), which was conducted from 2008 to 2010, OSHA found 

FAA Has Established Other 

Mechanisms to Report 

Safety Hazards at FAA 

Facilities

OSHA Inspections Provide 

Another Mechanism to 

Promote Workplace Safety
Page 27 GAO-13-757 Facilities Condition

deficiencies at 70 of the 75 air traffic control towers it inspected.49

Specifically, 279 violations were cited at the 70 towers. The most 

frequently cited violations at the towers were for the lack of smoke/fire 

stops throughout the towers, missing exit signage in emergency egress 

routes, storage of combustible materials, and failure to conduct stair 

pressurization-system testing. According to OSHA, as of February 2013, 

FAA has corrected these deficiencies, and all 75 towers now comply with 

the applicable egress and fire safety standards. Of the remaining towers, 

according to FAA, 77 are currently not compliant with OSHA standards for 

egress and fire safety, with an estimated cost of $57.5 million to repair 

them. According to FAA officials, it will take 4 years to upgrade the 

remaining towers to meet egress and fire safety standards.

FAA has taken steps to strengthen its capital-planning process to ensure 

its facilities are in good condition. We identified leading practices for using 

information to make capital-investment decisions primarily from GAO’s 

Executive Guide and OMB’s Capital Programming Guide (see table 8).50

We also drew from leading capital investment practices identified by the 

National Research Council. We compared FAA’s actions related to 

capital-planning and investment-decision making—focusing on operations 

facilities since they are the principal type of facility FAA maintains—to the 

criteria established in these guides.

 49 Because the unique design of air traffic control towers poses challenges to meeting 

standard OSHA egress and fire safety requirements, FAA developed an alternate 

standard specific to these facilities. Under its AIRTRAF inspection program, OSHA 

assessed air traffic control towers against this alternate standard. 

50 See footnote 6.

FAA Has Taken Steps 

to Strengthen Its 

Capital-Planning 

Process and 

Investment-Decision 

Practices That Are 

Generally Consistent 

with Leading 

Practices
Page 28 GAO-13-757 Facilities Condition

Table 8: Leading Capital-Planning Practices for Using Information to Make Capital-Investment Decisions

Leading practices Description

Needs assessment A comprehensive needs assessment identifies the resources needed to fulfill both 

immediate requirements and anticipated future needs based on the results-oriented goals 

and objectives that flow from the organization’s mission. A comprehensive assessment of 

needs considers the capability of existing resources and makes use of an accurate and 

up-to-date inventory of capital assets and facilities, as well as current information on asset 

condition. Using this information, an organization can make decisions about where to 

invest in facilities.

Review and approval of framework with 

established criteria for selecting capital 

investments

Agencies should establish a formal process for senior management to review and approve 

proposed capital assets. The cost of a proposed asset, the level of risk involved in 

acquiring the asset, and its importance to achieving the agency mission should be 

considered when defining criteria for executive review. Leading organizations have 

processes that determine the level of review and analysis based on the size, complexity, 

and cost of a proposed investment or its organization wide impact. As a part of this 

framework, proposed capital investments should be compared to one another to create a 

portfolio of major assets ranked in priority order.

Project prioritization Leading organizations have processes in which proposed capital investments should be 

compared to one another to create a portfolio of major assets ranked in priority order.

Strategic linkage Capital planning is an integral part of an agency’s strategic-planning process. It provides a 

long-range plan for the capital asset portfolio in order to meet the goals and objectives in 

the agency’s strategic and annual performance plans. Agency strategic and annual 

performance plans should identify capital assets and define how they will help the agency 

achieve its goals and objectives. Leading organizations also view strategic planning as the 

vehicle that guides decision making for all spending.

Long-term capital plan The long-term capital plan should be the final and principal product resulting from the 

agency’s capital-planning process. The capital plan should cover 5 years or more and 

should reflect decision makers’ priorities for the future. Leading organizations update longterm capital plans either annually or biennially. Agencies are encouraged to include 

certain elements in their capital plans, including a statement of the agency mission, 

strategic goals and objectives; a description of the agency’s planning process; baseline 

assessments and identification of performance gaps; and a risk management plan.

Source: GAO and OMB.

Leading practices suggest that to establish a baseline of condition and 

needs, organizations should maintain systems that track the use and 

performance of existing assets. FAA’s organizational components with 

responsibilities for managing facilities—ATO, the Aeronautical Center, 

and the Technical Center—have utilized technical consultants to inspect 

and determine the relative condition of building structures and systems. 

The inspections have resulted in the development of maintenance and 

repair requirements to correct identified deficiencies as documented in 

Needs Assessment
Page 29 GAO-13-757 Facilities Condition

summary reports. For example, ATO’s terminal and en-route and 

Aeronautical Center’s facility inspection reports show maintenance and 

repair requirements for major components at each facility.51

Leading practices also indicate that a comprehensive assessment of 

needs uses an accurate and up-to-date inventory of facilities as well as 

current information on their condition. While FAA’s consultants’ 

inspections provide current information on the condition of inspected 

facilities, the information on the condition of facilities that have not been 

inspected may be inaccurate. As previously discussed, ATO estimates 

the condition of most of the terminal facilities, and the method used to 

make the estimates produces results that may inaccurately reflect actual 

conditions and associated maintenance and repair needs. As a result, 

FAA cannot accurately determine any performance gap between current 

and needed conditions at its terminal facilities and is at risk of making 

suboptimal decisions about where to invest in maintenance and repairs.

Similarly, the 

Technical Center’s master plan contains component-specific information 

for facilities that indicate operability or need for replacement.

Leading practices call for a comprehensive decision-making framework to 

review, rank, and select from among competing project proposals. Such a 

framework should include the appropriate levels of management review, 

and selections should be based on established criteria. In January 2012, 

FAA created a Facilities Group Manager position within ATO to 

coordinate management of all its operations facilities, both staffed and 

unstaffed. Prior to this organizational change, managers of the different 

facility types—terminal facilities, en-route centers, and unstaffed 

facilities—acted independently in identifying requirements and prioritizing 

facility modernization and replacement projects. According to the 

Facilities Group Manager, under this previous organizational structure 

program managers of the different facility types competed with each other 

for funding and did not ensure common practices in planning and 

implementing modernization and replacement projects. As a result, 

managers likely applied different criteria in determining requirements and 

prioritizing projects so that investment decisions might not have 

addressed the most important needs of the operations facilities (ATO) 

portfolio. Going forward, the Facilities Group Manager’s goal is to ensure 

 51 Major building components include air handling units and ductwork, electrical 

distribution panels, lighting fixtures, lightning protection systems, uninterruptible power 

systems, and emergency generators, among others. 

Review and Approval of 

Framework with 

Established Criteria for 

Selecting Capital 

Investments
Page 30 GAO-13-757 Facilities Condition

the use of common criteria to prioritize projects across facility types and 

make investment decisions that best align with mission needs.

FAA organizational components responsible for managing facilities 

incorporate elements of leading practices in their approaches to 

prioritizing capital-investment projects. Leading capital-planning practices 

suggest that project prioritization processes use weighted criteria and 

consider long-term capital plans and project risk. FAA organizational 

components with facility management responsibility currently use 

weighted criteria that reflect risk considerations as illustrated by the 

following descriptions of their prioritization processes.

• En-route centers: ATO’s process for prioritizing projects at its en-route

centers weighs proposals (in decreasing order of importance) on their 

(1) direct operational requirement, (2) safety impact, (3) indirect 

operational requirement, and (4) FCI. ATO considers risk and places 

the most significant weight on projects to correct deficiencies that 

present direct risk to the safety of the National Airspace System 

(NAS).

• Terminal facilities: In prioritizing projects for its terminal facilities, ATO 

categorizes requirements in eight categories (in decreasing order of 

importance): (1) waterproofing; (2) heating, ventilation, and air 

conditioning; (3) electrical; (4) elevators; (5) plumbing; (6) operations 

areas special needs; (7) exterior components; and (8) interior finishes. 

ATO then assigns a priority rating to projects giving highest priority to 

items that are degrading, where mitigation is difficult, and where 

adverse impacts regularly occur. Lower priority is assigned in cases 

where previously planned repairs and improvements are anticipated 

to address identified needs.

• Technical Center: Technical Center bases its prioritization on the 

condition codes and importance factors assigned to individual 

components of its facilities. According to the Technical Center, each 

of the projects it has identified to date has been to repair or replace 

components that were in the poorest condition and of the greatest 

importance.

• Aeronautical Center: The Aeronautical Center determines its project 

prioritization list based on three factors: (1) FCI of the facility, (2) 

mission criticality, and (3) a facility designation factor. The 

Aeronautical Center first identifies facilities with an FCI below 95 

percent and subsequently eliminates facilities that are planned for 

Project Prioritization
Page 31 GAO-13-757 Facilities Condition

demolition or whose FCI is low based on deferred maintenance for 

non-critical building components. The remaining facilities are then 

ranked using the following two factors, FAA mission criticality52 and 

FAA facility designation.53

In reference to operations facilities, as indicated previously, ATO’s 

Facilities Group Manager is taking steps to develop a standard process 

for prioritizing projects across all facility types (en-route centers, terminal 

facilities, and unstaffed facilities). This single process is to replace the 

separate prioritization processes for en-route centers and terminal 

facilities described above. The new process considers operations, risk, 

employee safety, mission-critical needs, and environmental requirements 

as prioritization criteria. According to FAA officials, the new project 

prioritization process will be fully implemented by the fiscal year 2015 

budget cycle.

Once a facility receives an overall ranking, 

the Center does a more in-depth study on the facility’s actual 

condition and a business case analysis to determine detailed 

requirements.

Leading practices stress the importance of linking capital asset 

investments to an organization’s overall mission and long-term strategic 

goals and the development of a long-term capital investment plan to 

guide the implementation of those organizational goals and objectives 

and to help decision makers establish priorities over time. FAA has capital 

asset investment-planning efforts under way related to the consolidation 

of operations facilities and the transition to NextGen, key strategic 

initiatives of the agency. These planning efforts include:

• En-route center and TRACON consolidation: In November 2011, FAA 

approved an initial plan to consolidate en-route centers and 

TRACONs into six large, integrated facilities over the next two 

decades (through 2034). This long-term plan realigns and 

 52 Mission critical assets are those that house high-cost, mission critical equipment and 

technological systems, or assets that support the continuity of operations at the 

Aeronautical Center. 

53 FAA facility designation ranking is based on human occupancy levels and building size. 

The ranking with the highest score is a facility with over 151 employees and over 80,000 

square feet of space. The next ranking is a facility with between 11 and 150 employees 

and 2,500 to 80,000 square feet of space. The lowest ranking is for a facility with 10 or 

fewer employees and less than 2,500 square feet of space. 

Strategic Linkage and 

Long-term Capital Plan
Page 32 GAO-13-757 Facilities Condition

consolidates facilities based on operations, airspace responsibility, 

and geographic location. As we have previously concluded, 

reconfiguring facilities that handle air traffic control will be required to 

fully realize NextGen’s capabilities, reduce operating costs in the long 

term, and address sustainability issues with FAA’s current facility 

footprint.54 However, according to FAA officials, the implementation of 

this plan has been delayed due to significant funding reductions.

• Terminal facility consolidation: FAA has been developing a national 

facilities consolidation report in response to the FAA Modernization 

and Reform Act of 2012. The act requires FAA to make 

recommendations for realigning and consolidating FAA services and 

facilities and provide justification, projected costs and savings, and 

proposed timing for implementing each recommendation.55 FAA 

officials told us that the agency chartered a collaborative workgroup 

with labor unions to develop a process to address the act’s 

requirements. Their efforts will focus on TRACON realignments and 

consolidation. In July 2013, FAA officials noted that they had 

developed a process for identifying potential facilities for consolidation 

and realignment and were evaluating realignment options as required 

by the act, but had not yet identified which facilities would be 

consolidated or realigned or a time frame for developing such a list.56

• En-route and Terminal facility “Get Well” plan: ATO’s Facilities Group 

Manager is leading development of a 10-year plan that, among other 

things, establishes an approach to reduce the maintenance backlog at 

its existing facilities. According to data provided by the Facilities 

Group Manager in May 2013, ATO’s current overall deferred 

maintenance backlog for staffed operations facilities is $258.8 

 54 GAO, Department of Transportation: Key Issues and Management Challenges, 2013, 

GAO-13-402T (Washington, D.C.: Mar. 14, 2013).

55 FAA Modernization and Reform Act of 2012, Pub. L. No. 112-95, § 804, 126 

Stat.11,120 (Feb. 14, 2012).

56 Additionally, FAA’s contract with the air traffic controllers’ union requires that FAA notify 

the union as soon as possible but not less than one year in advance of the closure of a 

facility, facility consolidation, or inter-facility reorganization requiring reassignment of 

employees. This provision, along with the status of FAA’s realignment and consolidation 

efforts, suggests that it will be no less than 2 years before realignments and 

consolidations occur.
Page 33 GAO-13-757 Facilities Condition

million.57

These planning efforts are important to FAA’s ability to balance facility 

sustainment needs with NextGen requirements to ensure proper 

prioritization of projects. FAA’s Capital Investment Plan (CIP) provides 

insight into the agency’s long-term strategies for meeting these 

requirements. Leading practices emphasize the importance of developing 

a long-term capital investment plan to guide the implementation of 

organizational goals and objectives and to help decision makers establish 

priorities over time. Among the information provided in FAA’s CIP is 

projected funding for budget line items (BLI) for facility improvements and 

replacement as informed by the outcomes of the project prioritization 

processes discussed above. For example, table 9 illustrates BLIs specific 

to funding en-route-center and terminal-facility improvement and 

replacement projects. This shows that FAA’s fiscal year 2014 through 

2017 forecasts—with the exception of the terminal replacement budget 

line—are generally greater than actual past funding levels and 

significantly greater than levels in fiscal year 2013. ATO officials attributed 

increases in these budget lines in part to the better understanding of 

costs to upkeep facilities gained from its facility condition assessments. In 

reference to en-route centers, ATO officials noted another reason for 

expected increases in future budgets is a result of the aging of facilities 

that last received an influx of funds for modernization projects in the early 

1990s. Overall, ATO officials expect these forecast funding levels to result 

in a decrease in deferred maintenance and help them achieve their 95 

percent FCI target for facilities.

The plan will be based on meeting a target FCI of 95 percent 

for all facilities and establish compliance with safety requirements as a 

primary focus. ATO expects to complete this plan by September 2013.

 57 This amount comprises about 6 percent of FAA’s total deferred maintenance backlog 

for all staffed and unstaffed facilities. According to FAA officials, the backlog increases to 

$4.6 billion when factoring in the deferred maintenance for power systems, fuel storage 

tanks, and power cables as well as backlogs associated with environmental compliance 

and cleanup requirements. FAA expects this overall backlog is expected to grow to $7.5 

billion in 2024. However, as we note earlier in this report, we have concerns regarding 

how FAA estimates the condition and deferred maintenance of those facilities that have 

not been inspected. 
Page 34 GAO-13-757 Facilities Condition

Table 9: FAA’s Actual and Projected Capital Improvement Budget Line Items, Fiscal 

Years 2008 through 2017 (Dollars in Millions)

Budget line 

item Actual Projected

2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

En-route

center 

improvements 50.0 55.5 48.7 35.4 39 38.5 50.0 61.1 58.0 60.0

Terminal 

facility 

replacement 162.6 136.5 171.2 71.6 51.6 64.9 72.0 96.0 100.0 110.0

Terminal 

facility 

improvements 40.4 36.3 37.3 43.8 49.3 18.7 50.0 50.2 50.0 50.0

Source: FAA CIP data for fiscal years 2008 through 2017.

However, budget uncertainty may limit ATO’s ability to fund facilities 

projects as forecasted as well as limit efforts to implement facility 

consolidation and NextGen transition plans. The Balanced Budget and 

Emergency Deficit Control Act of 1985, as amended,58 places limits on 

discretionary spending through 2021. ATO officials indicated that in 

preparing the update to the CIP, they recognize that future funding levels 

may be less than forecast in the current plan. As a result, they are 

developing a two-tier system to prioritize projects. For example, instead of 

maintaining all facilities at a 95 percent FCI, they would focus on 

maintaining only facilities at the 56 busiest airports at this level and 

facilities at all other airports at a 90 percent FCI.

FAA staff occupy an array of facility types including air traffic control 

towers, administrative offices, and research laboratories in executing the 

agency’s mission to safely operate the NAS. The work environment 

defined by the condition of these facilities affects the safety and health of 

FAA employees. Inspecting facilities to gain information on their condition 

is important to FAA’s ability to identify repair and modernization 

requirements and direct resources to address them. However, FAA’s 

estimates of the condition of most terminal facilities—which represent a 

large segment of all FAA facilities—are inaccurate and lead to uncertainty 

in defining maintenance and repair needs. In addition, inaccuracies in 

 58 Pub. L. No. 99-177, title II, §§ 251–251A, 99 Stat. 1037 (Dec. 12, 1985), as amended.

Conclusions
Page 35 GAO-13-757 Facilities Condition

FAA’s agency-wide REMS data source and inconsistent data collection 

practices contribute to causing uncertainty about the composition and 

condition of its facility portfolio. Accurate and reliable information on 

facility condition is important not only to providing a safe and healthy 

working environment but also to prioritizing long-term needs for providing 

a physical infrastructure that enables FAA to effectively meet its mission 

while working to consolidate facilities and transition to NextGen. Having 

accurate and reliable information on facility conditions and associated 

maintenance and repair needs will help FAA optimize use of its 

resources, which are likely to be constrained in future years as a result of 

budget controls, and align its strategic and capital plans to reflect these 

constraints.

To ensure that FAA has accurate and reliable information on the condition 

of its facilities and allow for more informed decision making on their 

maintenance and repairs and associated capital-planning efforts, we 

recommend that the Secretary of Transportation direct the FAA 

Administrator to take the following two actions:

• Improve the precision of the estimation methods used by ATO to 

determine conditions at terminal facilities that have not been 

inspected and assess and report the error associated with estimates 

of the terminal facilities’ condition and deferred maintenance.

• Develop and implement a plan to comprehensively assess and 

improve REMS, consistent with sound data collection practices, to 

ensure that the data are sufficiently complete, accurate, and 

synchronized with other real property data maintained by FAA 

organizational components.

We provided the Departments of Labor and Transportation and the 

General Services Administration with a draft of this report for review and 

comment. The Department of Transportation provided technical 

comments, which we incorporated as appropriate. Neither the 

Department of Labor nor the General Services Administration had 

comments on the draft report.

We are sending copies of this report to relevant congressional 

committees, the Secretary of Transportation, and other interested parties. 

In addition, this report will also be available at no charge on GAO’s 

website at http://www.gao.gov.

Recommendations

Agency Comments
Page 36 GAO-13-757 Facilities Condition

If you or your staff have any questions about this report, please contact 

me at (202) 512-2834 or dillinghamg@gao.gov. Contact points for our 

Offices of Congressional Relations and Public Affairs may be found on 

the last page of this report. GAO staff who made key contributions to this 

report are listed in appendix III.

Gerald L. Dillingham, Ph.D.

Director, Physical Infrastructure
Appendix I: Objectives, Scope, and 

Methodology

Page 37 GAO-13-757 Facilities Condition

Section 610 of the Federal Aviation Administration (FAA) Modernization 

and Reform Act of 2012 mandated GAO to study the condition of FAAstaffed facilities.1

1. What is known about the conditions of FAA-staffed facilities and to 

what extent are the assessment methods and resulting data reliable?

In response to this mandate, we addressed the 

following objectives:

2. What have been the workplace injuries and illnesses reported by FAA 

employees in workers’ compensation claims, and to what extent has 

FAA met its targets for processing claims?

3. To what extent has FAA responded to safety deficiencies identified 

through its inspections and those conducted by the Occupational

Safety and Health Administration (OSHA)?

4. To what extent are actions FAA has taken to ensure that its facilities 

are in good condition, if any, consistent with leading practices for 

capital-investment decisions?

To determine what is known about the conditions of FAA-staffed facilities 

and the extent to which the methods used to make those determinations 

and the resulting data are reliable, we focused on staffed facilities that 

FAA or the General Services Administration (GSA) maintains.2

 1 FAA Modernization and Reform Act of 2012, Pub. L. No. 112-95, § 610, 126 Stat. 11, 

117 (Feb. 14, 2012).

We 

collected facility condition data from 2010 through 2012, including Facility 

Condition Indices (FCI) and deferred maintenance values for facilities, 

and compared the methods used by FAA and GSA in inspecting their 

facilities with generally accepted industry standards. Within FAA, we 

found two sources for facility condition data: the agency-wide Real Estate 

Management System (REMS) data and data from other FAA 

organizational components responsible for maintaining facilities. Early on, 

we found problems with REMS data and after discussions with REMS 

administrators and programmatic officials, we decided to use facility 

condition data from the FAA organizational components that are 

responsible for the facilities. Thus, we obtained facility data for en-route

and terminal facilities from the Air Traffic Organization. We also obtained 

2 To differentiate responsibility for maintaining facilities, we use the phrase “FAAmaintained” or “GSA-maintained.”

Appendix I: Objectives, Scope, and 

Methodology
Appendix I: Objectives, Scope, and 

Methodology

Page 38 GAO-13-757 Facilities Condition

data from the Mike Monroney Aeronautical Center (Aeronautical Center) 

and the William J. Hughes Technical Center (Technical Center) for their 

facilities. For FAA’s administrative facilities, we obtained condition data 

from the General Services Administration (GSA). The data we obtained 

represent different time frames (i.e., calendar year versus fiscal year). 

However, we used them because they were the only reliable data 

available. Further, the different sources of facility condition are based on 

differing methods. Therefore, in our analysis, we cannot compare the 

facility condition of one type of facility to other facility types. While we 

obtained the number of facilities leased by FAA and GSA, we did not 

obtain data on their condition because they did not exist or we determined 

that they were not reliable.

To assess the reliability of the FAA and GSA data we reviewed existing 

documentation about the data and interviewed agency officials and 

technical-consulting firm officials knowledgeable about the data. We 

performed electronic testing of the FAA data for obvious errors in 

accuracy and completeness. We found the data for FAA’s en-route

facilities, inspected terminal facilities, Aeronautical Center facilities, and 

GSA-maintained FAA facilities to be sufficiently reliable for describing 

facility condition. FAA’s Technical Center’s inspection process does not 

yield facility-level condition data, such as FCI. Rather, the process 

assesses the conditions of the components—such as structural, 

electrical, and heating/cooling systems—that comprise each facility. 

Because available data for Technical Center facilities does not reflect 

facility-level conditions similar to what we reported for other facility types, 

we do not present them in this report.

We did not find the condition data for FAA’s uninspected terminal facilities 

to be reliable and conducted further analysis to articulate our concerns 

with the reliability and accuracy; our findings are presented in greater 

detail in appendix II.

We also interviewed FAA and union officials representing major aviation 

employee groups about facility conditions. In addition, to observe 

conditions and to speak with knowledgeable staff to learn about any 

facility deficiencies and the projects for fixing them, we selected a nonprobability sample of facilities supporting operations and administrative 

functions in each of FAA’s three geographic service areas (see table 10). 

We also spoke with officials of the Technical Center by phone and 

obtained documents from them.
Appendix I: Objectives, Scope, and 

Methodology

Page 39 GAO-13-757 Facilities Condition

Table 10: FAA Facilities GAO Contacted

Eastern Service Area

FAA Headquarters 

William J. Hughes Technical Center

Washington, D.C., En-route Center

Central Service Area

Mike Monroney Aeronautical Center

Albuquerque Flight Standards District Office (FSDO)

Albuquerque En-route Center

Albuquerque Terminal Radar and Approach Control 

(TRACON) and Tower

Oklahoma City TRACON and Tower 

Western Service Area

Long Beach FSDO

Western Pacific Region Office

Los Angeles En-route Center 

Los Angeles Tower

Fullerton Tower (contract tower) 

Southern California TRACON 

Source: GAO analysis.

To determine the most common types of workplace injuries and illnesses 

FAA employees have reported, if any, we reviewed FAA and Department 

of Labor (Labor) workers’ compensation data from 2007 through 2012.3

 3 These data describe any claims submitted by employees for either (1) traumatic injury or 

(2) occupational disease or illness. In this report, we generally refer to these as claims for 

injuries and illnesses. 

To assess the reliability of the data we (1) reviewed existing 

documentation about the data, (2) interviewed agency officials 

knowledgeable about the data, and (3) performed electronic testing of the 

data for obvious errors in accuracy and completeness. We found the data 

to be sufficiently reliable for the purposes of this report. Because of the 

variability of factors contributing to causing reported injuries and illnesses, 

our study does not attempt to link workers compensation claims to facility 

conditions.
Appendix I: Objectives, Scope, and 

Methodology

Page 40 GAO-13-757 Facilities Condition

To determine the extent to which FAA responded to safety deficiencies 

identified through its inspections and those conducted by the 

Occupational Safety and Health Administration (OSHA), we interviewed 

FAA and OSHA officials as well as reviewed FAA and OSHA documents 

regarding this issue.

To determine the extent actions taken by FAA to ensure that its facilities 

are in good condition are consistent with leading practices for capitalinvestment decisions, we reviewed FAA’s Capital Investment Plan’s 

budget data (both actual and projected) for facility modernization and 

replacement, from 2008 through 2017. We also reviewed FAA’s process 

for making capital-investment decisions and compared it to GAO’s and 

Office of Management and Budget’s leading practices. We also 

interviewed FAA officials on their reorganization efforts and reviewed 

documents on FAA’s facility project prioritization schemes.

We conducted this performance audit from July 2012 to September 2013 

in accordance with generally accepted government auditing standards. 

Those standards require that we plan and perform the audit to obtain 

sufficient, appropriate evidence to provide a reasonable basis for our

findings and conclusions based on our audit objectives. We believe that 

the evidence obtained provides a reasonable basis for our findings and 

conclusions based on our audit objectives.
Appendix II: Assessment of FAA’s Statistical 

Model to Estimate the Condition of Terminal 

Facilities

Page 41 GAO-13-757 Facilities Condition

FAA estimates the condition of many terminal facilities using a statistical

model developed by a technical-consulting firm. The model estimates the 

condition of facilities that have not been physically inspected in the past 6

years, using data on the age and condition of facilities that have been 

inspected within that time period. The contractor has recommended that 

FAA revise its statistical models. In the 2012 roll-up report, the contractor 

notes that the baseline model is “preliminary and additional samples and 

adjustments to the formulas are needed for the results to be statistically 

valid.” In this appendix, we describe our replication of the FAA model, 

using data from the agency’s roll-up reports on facility condition, and 

assess the model’s statistical precision. In addition, we discuss several 

alternative models we considered and their precision relative to FAA’s 

baseline model.

FAA uses a combination of direct inspection, assumptions about the 

decline of a facility’s condition within 6 years of inspection, and statistical 

methods to estimate the condition of terminal facilities. For facilities that 

have been inspected in a given year, FAA uses the results of those 

inspections to estimate facility condition in that year. Over the next 5

years, FAA plans to update the condition of the facility from the baseline 

of its direct inspection, using a formula that incorporates assumptions 

about expected deterioration. After 6 years have elapsed since the 

inspection, FAA uses statistical methods to estimate facility condition.

The specific statistical method that FAA uses for these less recently 

inspected facilities is a regression model that predicts facility condition—

either the Facility Condition Index (FCI)1

yi = E(yi | agei) = α + βagei,

or deferred maintenance 

measured in dollars—as a function of facility age. Specifically, the model 

assumes that the unknown condition of a facility i is

,

with the intercept α fixed at 100 in the model of FCI and 0 in the model of 

deferred maintenance. FAA’s contractor fits the model to data on 

condition and facility age for facilities inspected within the past 6 years. 

 1 The FCI is equal to 100 - deferred maintenance / facility value. FAA has reported FCI as 

a percentage, but this scaling choice does not affect the analysis here.

Appendix II: Assessment of FAA’s Statistical 

Model to Estimate the Condition of Terminal 

Facilities

FAA Model Estimates 

Terminal Facility 

Condition with Substantial 

Imprecision
Appendix II: Assessment of FAA’s Statistical 

Model to Estimate the Condition of Terminal 

Facilities

Page 42 GAO-13-757 Facilities Condition

These inspection data estimate β and, thus, the unknown condition of 

facilities that were not inspected recently. In the 2012 roll-up report, FAA 

reports that β̂ = -0.203 for the model of FCI and β̂ = $12,668 for the 

model of deferred maintenance. Since the model requires FCI and 

deferred maintenance to equal zero when age equals to zero, the model 

predicts a facility’s condition using its age alone. For example, the 2012 

model would predict that all 10 year-old facilities have a FCI of 98.0 and 

deferred maintenance of $126,680, regardless of any other 

characteristics that could vary across the facilities.

All statistical estimates, including FAA’s predictions of facility condition, 

have estimation error associated with them. In this application, we are 

specifically interested in the prediction error of FAA’s model—that is, the 

amount by which FAA’s condition estimates for uninspected facilities can 

be expected to vary from the true condition that would be measured in 

new physical inspections. We can model this prediction error for each 

facility as

ei = yi − y�i = yi − β̂agei ,

which implies that

yi = β̂agei + ei .

Statistical models of the type that FAA uses to estimate facility condition 

typically assume that the error of prediction, ei

, varies randomly, such that 

E(ei) = 0 and Var(ei

) = σ2. If one applies this assumption to FAA’s model, 

the expected amount by which a new physical inspection of a facility with 

a fixed age would vary from FAA’s estimate is given by

Var(yi) = Var( y� + ei) = Var( y�) + σ2.

2

The expected error of a new inspection, given the FAA model’s 

prediction, is equal to the variance of the predicted value, which depends 

on the size of the sample used to estimate β and facility age, plus a term 

 2 See Jeffrey M. Wooldridge, Introductory Econometrics: a Modern Approach, 2nd ed. 

Mason, OH: Thomas South-Western, pp. 203-206.
Appendix II: Assessment of FAA’s Statistical 

Model to Estimate the Condition of Terminal 

Facilities

Page 43 GAO-13-757 Facilities Condition

σ2 measuring the variance of y around its mean for the population of 

facilities at a fixed age.3

In order to assess the precision of the FAA model estimates, we 

assembled data on facility age and the results of physical inspections 

from the 2010 through 2012 roll-up reports. For the 2010 sample, we 

assumed that all inspections which FAA defined as “actual” provided new 

data for analysis, even though many facilities were not physically 

inspected in 2010 but, instead, had values that were updated from an 

inspection conducted within the prior 6 years. This assumption was 

reasonable for our analysis, because 2010 was the first year in which the 

inspections were available to analyze. For the 2011-2012 sample, we 

treated inspections as providing new data only if they were conducted in 

those years. FAA considered inspections within 6 years of 2011 or 2012 

to have provided “actual” data on condition for the purpose of model 

estimation, but in practice, these data were mathematically adjusted from 

prior years. From a statistical perspective, these data are not new 

observations, because FAA only measured condition once, in the year the 

inspection occurred.4

We fit the FAA model to the 2010 sample of 114 facilities in order to 

replicate the estimates from the roll-up reports and assess their precision. 

The 2010 sample allowed us to assess the fit of the model on the same 

data used to estimate its parameters, also known as the “in-sample” fit. 

Using the model fitted to the 2010 sample, we predicted the condition of 

33 facilities that were physically inspected in either the 2011 or 2012 

samples. By comparing the condition predicted by the model to the actual 

condition measured in physical inspections, we estimated the model’s 

“out-of-sample” predictive power for new, unknown data. Evaluating a 

model’s ability to predict beyond the sample of data used to develop it 

helps avoid placing too much emphasis on random features of any one 

sample that can influence the model’s estimates. Moreover, the purpose 

of FAA’s model is to predict unknown facility conditions.

 3

This assumes that the population process generating the data used to estimate the 

model does not change between the time the model was estimated and the collection of 

new data.

4

More technically, these data could not have been new, random draws from a population 

data generation process, because they were calculated using a fixed mathematical 

formula. Our sample contrasts with the data FAA’s contractor uses to estimate the 

parameters of its prediction model, which uses data from all inspections conducted in the 

last 6 years.
Appendix II: Assessment of FAA’s Statistical 

Model to Estimate the Condition of Terminal 

Facilities

Page 44 GAO-13-757 Facilities Condition

Table 11 shows the results of our analysis, and figure 3 graphically 

depicts the 2010 data and model fit. We summarized the predictive 

accuracy of the FAA model using various statistics, in part due to the 

skewed distribution of FCI and deferred maintenance. Our estimated 

values of β— -0.227 on the FCI scale and $14,565 on the deferred 

maintenance scale—were similar to the values FAA reported in its 2010 

roll-up report (-0.225 and $12,551). However, our replication confirmed 

the contractor’s assessment that the FAA model does not predict facility 

condition with a high degree of precision. On the FCI scale, the root mean 

squared error (RMSE) of prediction—which is similar to the estimated 

variance of prediction error also reported in table 11—was 3.4 in the 2010 

sample used to estimate the model and 3.9 in the 2011-2012 validation 

sample. On the deferred maintenance scale, the RMSE was $606,862 in 

the estimation sample and $370,875 in the validation sample. The sample 

variance of FCI and deferred maintenance helps put the size of these 

results into context. In the estimation sample, the standard deviation was 

5.0 and the middle 50 percent of the FCI distribution ranged from 90.9 to 

96.6. The middle 50 percent of the deferred maintenance distribution 

ranged from $231,420 to $663,944, with a standard deviation of 

$565,421. These statistics are consistent with the large confidence 

intervals of prediction in figure 3. For example, the deferred-maintenance 

predictions for 10 and 40 year-old facilities have 95 percent confidence 

intervals ranging from 0 to $1,353,723 and from 0 to $1,797,599, 

respectively.5 Together, these results show that FAA’s estimates of facility 

condition vary meaningfully from the results of physical inspections.

 5

The confidence intervals are truncated at zero, because the deferred maintenance and 

FCI must be non-negative.
Appendix II: Assessment of FAA’s Statistical 

Model to Estimate the Condition of Terminal 

Facilities

Page 45 GAO-13-757 Facilities Condition

Table 11: Results of Replication and Predictive Validation of FAA Model

Facility Condition Index 

(0-100)

Deferred Maintenance

(dollars)

2010 Sample 

(estimation 

and 

prediction)

2011-2012 

Sample 

(prediction 

only)

2010 Sample 

(estimation 

and 

prediction)

2011-2012 

Sample 

(prediction 

only)

Parameters

ß -0.227 NA 14,565 NA

σ 3.392 NA 609,500 NA

Fit statistics

Root mean squared 

error

3.377 3.869 606,862 370,875

Root median 

squared error

1.524 1.823 217,415 221,592

Mean absolute error 2.371 2.690 343,660 280,211

Median absolute 

error

1.524 1.823 217,400 221,592

Total error NA NA 13,255,775 -2,417,559

Total absolute error NA NA 39,177,277 9,246,953

N 114 33 114 33

Source: GAO analysis of FAA roll-up report data.

Note: Entries in the “2010 sample” columns are estimates from a FAA statistical model of facility 

condition fit to data from the agency’s 2010 roll-up report on this topic. We used the estimated 

model to predict the condition of facilities that were physically inspected in 2011 or 2012. Entries in 

the “2011-2012” sample columns are statistics summarizing the predictive accuracy of the 2010 

model on these later data.
Appendix II: Assessment of FAA’s Statistical 

Model to Estimate the Condition of Terminal 

Facilities

Page 46 GAO-13-757 Facilities Condition

Figure 3: Estimated versus Actual Deferred Maintenance in 2010

Given the imprecision of FAA’s model, we analyzed data available from 

the agency’s roll-up reports to assess whether alternative methods could 

predict terminal facility condition more accurately. We measured the 

following variables for the same facilities and time periods described 

above: facility size (square footage); geographic location, including the 

facility’s latitude and longitude; architectural design type; class of facility 

by function, such as whether a facility was a “tower with radar” or 

“combined TRACON and tower;” and whether FAA maintained and/or 

owned the facility (respectively). To measure facility value, we calculated 

the value implied by FAA’s data on FCI and deferred maintenance.

Alternative Methods Can 

Improve the Precision of 

Some Facility Condition 

Estimates
Appendix II: Assessment of FAA’s Statistical 

Model to Estimate the Condition of Terminal 

Facilities

Page 47 GAO-13-757 Facilities Condition

We used several approaches to systematically search for alternative 

prediction methods, collectively known as “data mining” techniques. As 

with our evaluation of the baseline FAA model, we used the 2010 sample 

for estimating and comparing models and the 2011-2012 sample for 

validating the predictions on new data. We would have preferred to divide 

the available data into three parts to estimate, refine, and test alternative 

models, as recommended by methodological guidance on data mining. 

The small sample size precluded this approach, however.

Our first approach involved estimating a series of linear regression 

models that added various combinations of the variables above as 

predictors to the baseline FAA model. This “stepwise” search produced a 

model that minimized the Akaike Information Criterion (AIC), which is 

closely related to the residual sum of squares and R-squared statistics for 

the type of linear Normal models used by FAA. This procedure did not 

identify a more predictive model than the baseline FAA model, but it did 

identify a more predictive model of deferred maintenance:

E(DMi | xi) = β1agei + β2valuei + β3agei ∙ valuei + designiδ + classiθ

+ owneriγ

(GAO Model D1)

Our second approach used recursive partitioning or “tree” methods to 

predict facility condition. This approach placed facilities into groups 

defined by the covariates, and then estimated condition as the mean 

within each group. Various classifications of facilities into covariate 

groups were searched to minimize the Akaike Information Criterion, which 

implicitly considered interactions and non-linearities among the 

covariates. In this sense, a recursive partitioning search complemented 

our application of stepwise methods, which assumed that all variables 

had linear relationships and no interactions (except for latitude and 

longitude). The clustering, non-linearity, and skewness in the distribution 

of facility condition (see fig. 3) makes these assumptions somewhat 

unrealistic. Fitting a constant value for each group may be more 

appropriate, given these features of the data. Partitioning methods require 

“pruning,” a process in which covariate groups of various sizes are 

searched to minimize the bias (average error) of the predictions while 

controlling their variance. We chose the pruning parameter that minimized 

the mean prediction error over 10 cross-validated samples of the 2010 
Appendix II: Assessment of FAA’s Statistical 

Model to Estimate the Condition of Terminal 

Facilities

Page 48 GAO-13-757 Facilities Condition

data.6

E(FCIi | xi)

The final tree implied the following piecewise constant regression 

models for FCI and deferred maintenance:

= β0 + β1I(9. 5 ≤ agei < 24. 5) +

β2I(24. 5 ≤ agei < 47. 5,latitudei ≥ 30. 46) +

β3I(24.5 ≤ agei < 47.5,latitudei < 30.46) + β4I(agei > 47.5)

(GAO Model F1)

E(DMi | xi) = β0 + β1I(TRACONi = 0, agei < 6.5) +

β2I(TRACONi = 0, agei ≥ 6.5, valuei < 4,275,383) +

β3I(TRACONi = 0, 6.5 ≤ agei < 47.5, 4,275,383 ≤ valuei < 7,381,382) +

β4I(TRACONi = 0, agei ≥ 47.5, 4,275,383 ≤ valuei < 7,381,382)

β5I(TRACONi = 0, 6.5 ≤ agei < 30.5, valuei ≥ 7,381,382) +

β6I(TRACONi = 0, agei ≥ 30.5, valuei ≥ 7,381,382)

(GAO Model D2),

where I(.) is the indicator function and TRACONi equals 1 if the 

architectural design was a “Large TRACON” and 0 otherwise. Note that 

the intercept estimates the mean for large TRACONs. Fitting separate 

values according to whether the facility is a large TRACON is consistent 

with the data in figure 3, which shows that this class of facility often 

produces large outliers with respect to the mean value conditional on age 

and with respect to the marginal distribution of facility value.7

In addition to searching broadly over the available data to improve 

prediction, we developed a model that simply adjusted the FAA baseline 

approach to predicting deferred maintenance by incorporating the 

facility’s value (calculated as the cost of facility replacement):

In addition, 

constant fits may better estimate the condition of very young facilities, 

which cluster toward a FCI of 100 and deferred maintenance of $0.

 6

Trevor Hastie, Robert Tibshirani, and Jerome Friedman, The Elements of Statistical 

Learning (New York: Springer-Verlag, 2001) discusses cross-validation and pruning for 

recursive partitioning methods in more detail.

7

A similar version of the tree model of deferred maintenance is a three-way interaction of 

age, facility value, and an indicator for whether the facility was a large TRACON. The outof-sample RMSE of the three-way interaction model was $272,169, compared to $263,292 

for the tree model. Alternatively, one could estimate a model with the two-way interaction 

of age and value separately for large TRACONs and all other facilities.
Appendix II: Assessment of FAA’s Statistical 

Model to Estimate the Condition of Terminal 

Facilities

Page 49 GAO-13-757 Facilities Condition

E(DMi | xi) = β1agei + β2valuei + β3agei ∙ valuei

(GAO Model D3)

This model makes the effects of age and value conditional on the other 

variable, so that deferred maintenance can vary across facilities of the 

same age. In contrast, the baseline FAA model assumes that all facilities 

of the same age have the same deferred maintenance, which ignores the 

fact that facilities of the same age vary widely in value and, thus, deferred 

maintenance.

As shown in table 12, our alternative models predicted deferred 

maintenance more precisely than FAA’s baseline model. On the deferred 

maintenance scale, our models improved the RMSE of deferred 

maintenance by at least $234,385 (39 percent) in the 2010 estimation 

sample and by $118,065 (32 percent) in the 2011-2012 validation sample. 

When assessed on other fit statistics, our models of deferred 

maintenance typically outperform FAA’s baseline. The difference is 

largely due to the fact that our models incorporate facility value when 

predicting deferred maintenance, which should explain a large proportion 

of the variation across facilities of varying size. In contrast, we were 

unable to substantially improve FAA’s model of FCI. The RMSE of our 

tree-selected model was 8.6 percent smaller than that of the FAA 

baseline in the 2010 sample, but the fit statistics did not consistently favor 

either model in the new 2011-2012 sample. FAA might prefer one model 

or another on these measures of fit, according to the goals of prediction. 

For example, if FAA sought to minimize to the error of the estimated total 

deferred maintenance, the total error or total absolute error would be 

appropriate measures of prediction accuracy.
Appendix II: Assessment of FAA’s Statistical 

Model to Estimate the Condition of Terminal 

Facilities

Page 50 GAO-13-757 Facilities Condition

Table 12: Results of Replication and Predictive Validation of FAA Model

Root 

mean 

squared 

error

Root 

median 

squared 

error

Mean 

absolute 

error

Median 

absolute 

error Total error

Total 

absolute 

error

FCI (0-100)

2010 Sample

FAA baseline 3.377 1.524 2.371 1.524 NA NA

GAO model F1 3.088 1.519 2.177 1.519 NA NA

2011-2012 

Sample

FAA baseline 3.869 1.823 2.690 1.823 NA NA

GAO model F1 4.221 1.663 3.143 1.663 NA NA

Deferred 

Maintenance 

(dollars)

2010 Sample

 FAA model, 606,862 217,415 343,660 217,400 13,255,775 39,177,277

 GAO model D1 288,431 138,714 195,861 138,713 0 21,152,937

 GAO model D2 303,155 99,441 175,479 99,438 0 20,004,600

 GAO model D3 372,477 156,211 238,010 156,205 -1,106,601 25,705,067

2011-2012 Sample

 FAA model 370,875 221,592 280,211 221,592 -2,417,559 9,246,953

 GAO model D1 294,992 244,965 232,250 244,965 -1,802,472 6,270,737

 GAO model D2 263,292 126,139 187,338 126,102 -608,089 5,994,801

 GAO model D3 252,810 157,797 187,201 157,797 -810,940 5,054,426

Source: GAO analysis of FAA roll-up report data.

Note: Entries are fit statistics of statistical models developed on a sample of 114 facilities from the 

2010 FAA roll-up report. Results for the 2010 sample are the in-sample fit statistics, while results for 

the 2011-2012 sample are out-of-sample fit statistics.

Our analysis suggests that data available to FAA would allow the agency 

to substantially improve its model of deferred maintenance. Specifically, 

incorporating facility value along with age and perhaps facility class and 

architectural design type would better exploit the available data. 

Additional revisions also may be appropriate, depending on the available 

data. FAA could refine the mathematical form of the model over time, as 

new inspections are conducted to provide additional data for model 

validation.

Implications for Revising 

Prediction Models
Appendix II: Assessment of FAA’s Statistical 

Model to Estimate the Condition of Terminal 

Facilities

Page 51 GAO-13-757 Facilities Condition

Although we were unable to improve upon FAA’s model of FCI, the best 

available model still does not predict FCI with a high degree of precision. 

Additional data beyond the variables available to us in the roll-up reports 

may help identify a more predictive model. For example, data on typical 

weather conditions, usage, or building materials may improve predictions 

of FCI beyond what is possible using the variables we considered here 

and FAA’s consultant has considered previously. If these data are 

available and are correlated with condition and if their collection and 

analysis costs less than the error caused by FAA’s baseline model, 

incorporating additional variables could be a cost-effective solution to 

estimating FCI for facilities that have not been physically inspected in 

recent years.

Our findings are consistent with those of FAA’s consultant, which has 

recommended that FAA revise its statistical models. In its 2012 roll-up 

report, the consultant notes that the baseline model is “preliminary and 

additional samples and adjustments to the formulas are needed for the 

results to be statistically valid.” They recommended addressing outliers in 

the distribution of facilities and including additional predictors of facility 

condition.8 In a 2008 report, the contractor recommended adjusting the 

physical inspection process to ensure a representative sample is 

available for statistical analysis.9 The latter recommendation could be 

implemented as an inspection plan that selects facilities according to 

known probabilities, which would ensure that estimates of facility 

condition are unbiased and have known sampling variances. The sample 

could be designed in such a way to incorporate known maintenance 

problems or inspection needs, such as by selecting facilities for inspection 

with unequal probabilities from within strata defined by age, size, or other 

important variables. A probability sample could be particularly useful for 

reporting average or total condition across facilities.

 8

Jacobs Engineering, “Organizational 2012 Final MARS Roll-Up Report for 128 ATCTTRACON Sites (January 2007 – December 2012),” January 2013, pp. 24-26.

9

Jacobs Engineering, “Organizational Roll-Up Report for 109 ATCT – TRACON Sites,”

November 2008, Appendix C, pp. 2, 5.
Appendix III: GAO Contact and Staff 

Acknowledgments

Page 52 GAO-13-757 Facilities Condition

Gerald L. Dillingham, Ph.D., (202) 512-2834, or dillinghamg@gao.gov

In addition to the individual named above, GAO staff who made key 

contributions to this report are Michael Armes, Assistant Director; Martha 

Chow; Colin Fallon; James Geibel; Kathleen Gilhooly; Daniel Hoy; Grant 

Mallie; SaraAnn Moessbauer; and Jeff Tessin.

Appendix III: GAO Contact and Staff 

Acknowledgments

GAO Contact

Staff 

Acknowledgments

(540249)
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